remove agent.md

Co-authored-by: Varun Chawla <varun_6april@hotmail.com>
Co-authored-by: aziamimoh <aziamimoh@users.noreply.github.com>
Co-authored-by: pgzcoa <pgzcoa@users.noreply.github.com>
Co-authored-by: TinaZhang24 <TinaZhang24@users.noreply.github.com>

.eslintrc.json

@@ -39,5 +39,26 @@
         "allowReferrer": true
       }
     ]
-  }
+  },
+  "overrides": [
+    {
+      "files": ["packages/excalidraw/**/*.{ts,tsx}"],
+      "excludedFiles": ["packages/excalidraw/**/*.test.{ts,tsx}", "packages/excalidraw/**/*.test.*.{ts,tsx}"],
+      "rules": {
+        "@typescript-eslint/no-restricted-imports": [
+          "error",
+          {
+            "patterns": [
+              {
+                "group": ["@excalidraw/excalidraw"],
+                "message": "Do not import from the barrel 'index.tsx' files. Use direct relative imports to the specific module instead.",
+                "allowTypeImports": true
+              }
+            ],
+            "paths": [".", "..", "../..", "../../..", "../../../..", "../../../../..", "../index", "../../index", "../../../index", "../../../../index"]
+          }
+        ]
+      }
+    }
+  ]
 }

dev-docs/docs/@excalidraw/excalidraw/api/excalidraw-element-skeleton.mdx

@@ -172,7 +172,7 @@ convertToExcalidrawElements([
     type: "arrow",
     x: 450,
     y: 20,
-    startArrowhead: "dot",
+    startArrowhead: "circle",
     endArrowhead: "triangle",
     strokeColor: "#1971c2",
     strokeWidth: 2,

examples/with-script-in-browser/initialData.tsx

@@ -1,4 +1,4 @@
-import type { ExcalidrawElementSkeleton } from "@excalidraw/excalidraw/data/transform";
+import type { ExcalidrawElementSkeleton } from "@excalidraw/excalidraw/element/transform";
 import type { FileId } from "@excalidraw/excalidraw/element/types";
 
 const elements: ExcalidrawElementSkeleton[] = [

examples/with-script-in-browser/package.json

@@ -3,14 +3,14 @@
   "version": "1.0.0",
   "private": true,
   "dependencies": {
-    "react": "19.0.0",
-    "react-dom": "19.0.0",
     "@excalidraw/excalidraw": "*",
-    "browser-fs-access": "0.29.1"
+    "browser-fs-access": "0.38.0",
+    "react": "19.0.0",
+    "react-dom": "19.0.0"
   },
   "devDependencies": {
-    "vite": "5.0.12",
-    "typescript": "^5"
+    "typescript": "^5",
+    "vite": "5.0.12"
   },
   "scripts": {
     "start": "vite",

examples/with-script-in-browser/utils.ts

@@ -4,8 +4,6 @@ import { unstable_batchedUpdates } from "react-dom";
 
 type FILE_EXTENSION = Exclude<keyof typeof MIME_TYPES, "binary">;
 
-const INPUT_CHANGE_INTERVAL_MS = 500;
-
 export type ResolvablePromise<T> = Promise<T> & {
   resolve: [T] extends [undefined] ? (value?: T) => void : (value: T) => void;
   reject: (error: Error) => void;
@@ -54,40 +52,6 @@ export const fileOpen = <M extends boolean | undefined = false>(opts: {
     extensions,
     mimeTypes,
     multiple: opts.multiple ?? false,
-    legacySetup: (resolve, reject, input) => {
-      const scheduleRejection = debounce(reject, INPUT_CHANGE_INTERVAL_MS);
-      const focusHandler = () => {
-        checkForFile();
-        document.addEventListener("keyup", scheduleRejection);
-        document.addEventListener("pointerup", scheduleRejection);
-        scheduleRejection();
-      };
-      const checkForFile = () => {
-        // this hack might not work when expecting multiple files
-        if (input.files?.length) {
-          const ret = opts.multiple ? [...input.files] : input.files[0];
-          resolve(ret as RetType);
-        }
-      };
-      requestAnimationFrame(() => {
-        window.addEventListener("focus", focusHandler);
-      });
-      const interval = window.setInterval(() => {
-        checkForFile();
-      }, INPUT_CHANGE_INTERVAL_MS);
-      return (rejectPromise) => {
-        clearInterval(interval);
-        scheduleRejection.cancel();
-        window.removeEventListener("focus", focusHandler);
-        document.removeEventListener("keyup", scheduleRejection);
-        document.removeEventListener("pointerup", scheduleRejection);
-        if (rejectPromise) {
-          // so that something is shown in console if we need to debug this
-          console.warn("Opening the file was canceled (legacy-fs).");
-          rejectPromise(new Error("Request Aborted"));
-        }
-      };
-    },
   }) as Promise<RetType>;
 };
 

excalidraw-app/App.tsx

@@ -5,6 +5,8 @@ import {
   CaptureUpdateAction,
   reconcileElements,
   useEditorInterface,
+  ExcalidrawAPIProvider,
+  useExcalidrawAPI,
 } from "@excalidraw/excalidraw";
 import { trackEvent } from "@excalidraw/excalidraw/analytics";
 import { getDefaultAppState } from "@excalidraw/excalidraw/appState";
@@ -34,7 +36,6 @@ import {
 import polyfill from "@excalidraw/excalidraw/polyfill";
 import { useCallback, useEffect, useRef, useState } from "react";
 import { loadFromBlob } from "@excalidraw/excalidraw/data/blob";
-import { useCallbackRefState } from "@excalidraw/excalidraw/hooks/useCallbackRefState";
 import { t } from "@excalidraw/excalidraw/i18n";
 
 import {
@@ -74,6 +75,7 @@ import type {
   BinaryFiles,
   ExcalidrawInitialDataState,
   UIAppState,
+  ExcalidrawProps,
 } from "@excalidraw/excalidraw/types";
 import type { ResolutionType } from "@excalidraw/common/utility-types";
 import type { ResolvablePromise } from "@excalidraw/common/utils";
@@ -114,6 +116,7 @@ import {
 } from "./data";
 
 import { updateStaleImageStatuses } from "./data/FileManager";
+import { FileStatusStore } from "./data/fileStatusStore";
 import {
   importFromLocalStorage,
   importUsernameFromLocalStorage,
@@ -369,6 +372,8 @@ const initializeScene = async (opts: {
 };
 
 const ExcalidrawWrapper = () => {
+  const excalidrawAPI = useExcalidrawAPI();
+
   const [errorMessage, setErrorMessage] = useState("");
   const isCollabDisabled = isRunningInIframe();
 
@@ -399,9 +404,6 @@ const ExcalidrawWrapper = () => {
     }, VERSION_TIMEOUT);
   }, []);
 
-  const [excalidrawAPI, excalidrawRefCallback] =
-    useCallbackRefState<ExcalidrawImperativeAPI>();
-
   const [, setShareDialogState] = useAtom(shareDialogStateAtom);
   const [collabAPI] = useAtom(collabAPIAtom);
   const [isCollaborating] = useAtomWithInitialValue(isCollaboratingAtom, () => {
@@ -433,18 +435,15 @@ const ExcalidrawWrapper = () => {
     }
   }, [excalidrawAPI]);
 
-  useEffect(() => {
-    if (!excalidrawAPI || (!isCollabDisabled && !collabAPI)) {
-      return;
-    }
-
-    const loadImages = (
-      data: ResolutionType<typeof initializeScene>,
-      isInitialLoad = false,
-    ) => {
-      if (!data.scene) {
+  // ---------------------------------------------------------------------------
+  // Hoisted loadImages
+  // ---------------------------------------------------------------------------
+  const loadImages = useCallback(
+    (data: ResolutionType<typeof initializeScene>, isInitialLoad = false) => {
+      if (!data.scene || !excalidrawAPI) {
         return;
       }
+
       if (collabAPI?.isCollaborating()) {
         if (data.scene.elements) {
           collabAPI
@@ -471,6 +470,12 @@ const ExcalidrawWrapper = () => {
           }, [] as FileId[]) || [];
 
         if (data.isExternalScene) {
+          if (fileIds.length) {
+            // Direct Firebase call (not through FileManager), so track manually
+            FileStatusStore.updateStatuses(
+              fileIds.map((id) => [id, "loading"]),
+            );
+          }
           loadFilesFromFirebase(
             `${FIREBASE_STORAGE_PREFIXES.shareLinkFiles}/${data.id}`,
             data.key,
@@ -482,12 +487,18 @@ const ExcalidrawWrapper = () => {
               erroredFiles,
               elements: excalidrawAPI.getSceneElementsIncludingDeleted(),
             });
+            FileStatusStore.updateStatuses([
+              ...loadedFiles.map((f) => [f.id, "loaded"] as [FileId, "loaded"]),
+              ...[...erroredFiles.keys()].map(
+                (id) => [id, "error"] as [FileId, "error"],
+              ),
+            ]);
           });
         } else if (isInitialLoad) {
           if (fileIds.length) {
             LocalData.fileStorage
               .getFiles(fileIds)
-              .then(({ loadedFiles, erroredFiles }) => {
+              .then(async ({ loadedFiles, erroredFiles }) => {
                 if (loadedFiles.length) {
                   excalidrawAPI.addFiles(loadedFiles);
                 }
@@ -500,10 +511,19 @@ const ExcalidrawWrapper = () => {
           }
           // on fresh load, clear unused files from IDB (from previous
           // session)
-          LocalData.fileStorage.clearObsoleteFiles({ currentFileIds: fileIds });
+          LocalData.fileStorage.clearObsoleteFiles({
+            currentFileIds: fileIds,
+          });
         }
       }
-    };
+    },
+    [collabAPI, excalidrawAPI],
+  );
+
+  useEffect(() => {
+    if (!excalidrawAPI || (!isCollabDisabled && !collabAPI)) {
+      return;
+    }
 
     initializeScene({ collabAPI, excalidrawAPI }).then(async (data) => {
       loadImages(data, /* isInitialLoad */ true);
@@ -628,7 +648,7 @@ const ExcalidrawWrapper = () => {
         false,
       );
     };
-  }, [isCollabDisabled, collabAPI, excalidrawAPI, setLangCode]);
+  }, [isCollabDisabled, collabAPI, excalidrawAPI, setLangCode, loadImages]);
 
   useEffect(() => {
     const unloadHandler = (event: BeforeUnloadEvent) => {
@@ -773,6 +793,56 @@ const ExcalidrawWrapper = () => {
     [setShareDialogState],
   );
 
+  // ---------------------------------------------------------------------------
+  // onExport — intercepts file save to wait for pending image loads
+  // ---------------------------------------------------------------------------
+  const onExport: Required<ExcalidrawProps>["onExport"] = useCallback(
+    async function* () {
+      let snapshot = FileStatusStore.getSnapshot();
+      const { pending, total } = FileStatusStore.getPendingCount(
+        snapshot.value,
+      );
+      if (pending === 0) {
+        return;
+      }
+
+      // Yield initial progress
+      yield {
+        type: "progress",
+        progress: (total - pending) / total,
+        message: `Loading images (${total - pending}/${total})...`,
+      };
+
+      // Wait for all pending images to finish
+      while (true) {
+        snapshot = await FileStatusStore.pull(snapshot.version);
+        const { pending: nowPending, total: nowTotal } =
+          FileStatusStore.getPendingCount(snapshot.value);
+
+        yield {
+          type: "progress",
+          progress: (nowTotal - nowPending) / nowTotal,
+          message: `Loading images (${nowTotal - nowPending}/${nowTotal})...`,
+        };
+
+        if (nowPending === 0) {
+          await new Promise((r) => setTimeout(r, 500));
+          yield {
+            type: "progress",
+            message: `Preparing export...`,
+          };
+          return;
+        }
+      }
+    },
+    [],
+  );
+
+  // const onExport = () => {
+  //   return new Promise((r) => setTimeout(r, 2500));
+  //   // console.log("onExport");
+  // };
+
   // browsers generally prevent infinite self-embedding, there are
   // cases where it still happens, and while we disallow self-embedding
   // by not whitelisting our own origin, this serves as an additional guard
@@ -839,8 +909,8 @@ const ExcalidrawWrapper = () => {
       })}
     >
       <Excalidraw
-        excalidrawAPI={excalidrawRefCallback}
         onChange={onChange}
+        onExport={onExport}
         initialData={initialStatePromiseRef.current.promise}
         isCollaborating={isCollaborating}
         onPointerUpdate={collabAPI?.onPointerUpdate}
@@ -1206,7 +1276,9 @@ const ExcalidrawApp = () => {
   return (
     <TopErrorBoundary>
       <Provider store={appJotaiStore}>
-        <ExcalidrawWrapper />
+        <ExcalidrawAPIProvider>
+          <ExcalidrawWrapper />
+        </ExcalidrawAPIProvider>
       </Provider>
     </TopErrorBoundary>
   );

excalidraw-app/collab/Collab.tsx

@@ -72,6 +72,7 @@ import {
   FileManager,
   updateStaleImageStatuses,
 } from "../data/FileManager";
+import { FileStatusStore } from "../data/fileStatusStore";
 import { LocalData } from "../data/LocalData";
 import {
   isSavedToFirebase,
@@ -149,6 +150,7 @@ class Collab extends PureComponent<CollabProps, CollabState> {
     };
     this.portal = new Portal(this);
     this.fileManager = new FileManager({
+      onFileStatusChange: FileStatusStore.updateStatuses.bind(FileStatusStore),
       getFiles: async (fileIds) => {
         const { roomId, roomKey } = this.portal;
         if (!roomId || !roomKey) {

excalidraw-app/components/DebugCanvas.tsx

@@ -414,7 +414,6 @@ export const debugRenderer = throttleRAF(
   ) => {
     _debugRenderer(canvas, appState, elements, scale);
   },
-  { trailing: true },
 );
 
 export const loadSavedDebugState = () => {

excalidraw-app/data/FileManager.ts

@@ -40,10 +40,12 @@ export class FileManager {
 
   private _getFiles;
   private _saveFiles;
+  private _onFileStatusChange;
 
   constructor({
     getFiles,
     saveFiles,
+    onFileStatusChange,
   }: {
     getFiles: (fileIds: FileId[]) => Promise<{
       loadedFiles: BinaryFileData[];
@@ -53,9 +55,13 @@ export class FileManager {
       savedFiles: Map<FileId, BinaryFileData>;
       erroredFiles: Map<FileId, BinaryFileData>;
     }>;
+    onFileStatusChange?: (
+      updates: Array<[FileId, "loading" | "loaded" | "error"]>,
+    ) => void;
   }) {
     this._getFiles = getFiles;
     this._saveFiles = saveFiles;
+    this._onFileStatusChange = onFileStatusChange;
   }
 
   /**
@@ -146,6 +152,8 @@ export class FileManager {
       this.fetchingFiles.set(id, true);
     }
 
+    this._onFileStatusChange?.(ids.map((id) => [id, "loading"]));
+
     try {
       const { loadedFiles, erroredFiles } = await this._getFiles(ids);
 
@@ -156,6 +164,13 @@ export class FileManager {
         this.erroredFiles_fetch.set(fileId, true);
       }
 
+      this._onFileStatusChange?.([
+        ...loadedFiles.map((f) => [f.id, "loaded"] as [FileId, "loaded"]),
+        ...[...erroredFiles.keys()].map(
+          (id) => [id, "error"] as [FileId, "error"],
+        ),
+      ]);
+
       return { loadedFiles, erroredFiles };
     } finally {
       for (const id of ids) {
@@ -195,6 +210,13 @@ export class FileManager {
   };
 
   reset() {
+    if (this._onFileStatusChange && this.fetchingFiles.size) {
+      this._onFileStatusChange(
+        [...this.fetchingFiles.keys()].map(
+          (id) => [id, "error"] as [FileId, "error"],
+        ),
+      );
+    }
     this.fetchingFiles.clear();
     this.savingFiles.clear();
     this.savedFiles.clear();

excalidraw-app/data/LocalData.ts

@@ -42,6 +42,7 @@ import type { MaybePromise } from "@excalidraw/common/utility-types";
 import { SAVE_TO_LOCAL_STORAGE_TIMEOUT, STORAGE_KEYS } from "../app_constants";
 
 import { FileManager } from "./FileManager";
+import { FileStatusStore } from "./fileStatusStore";
 import { Locker } from "./Locker";
 import { updateBrowserStateVersion } from "./tabSync";
 
@@ -166,6 +167,7 @@ export class LocalData {
   // ---------------------------------------------------------------------------
 
   static fileStorage = new LocalFileManager({
+    onFileStatusChange: FileStatusStore.updateStatuses.bind(FileStatusStore),
     getFiles(ids) {
       return getMany(ids, filesStore).then(
         async (filesData: (BinaryFileData | undefined)[]) => {

excalidraw-app/data/fileStatusStore.ts

@@ -0,0 +1,48 @@
+import { VersionedSnapshotStore } from "@excalidraw/common";
+
+import type { FileId } from "@excalidraw/element/types";
+
+export type FileLoadingStatus = "loading" | "loaded" | "error";
+
+export class FileStatusStore {
+  private static store = new VersionedSnapshotStore<
+    Map<FileId, FileLoadingStatus>
+  >(new Map());
+
+  static getSnapshot() {
+    return this.store.getSnapshot();
+  }
+
+  static pull(sinceVersion?: number) {
+    return this.store.pull(sinceVersion);
+  }
+
+  static updateStatuses(updates: Array<[FileId, FileLoadingStatus]>) {
+    if (!updates.length) {
+      return;
+    }
+    this.store.update((prev) => {
+      let changed = false;
+      const next = new Map(prev);
+      for (const [id, status] of updates) {
+        if (next.get(id) !== status) {
+          next.set(id, status);
+          changed = true;
+        }
+      }
+      return changed ? next : prev;
+    });
+  }
+
+  static getPendingCount(statuses: Map<FileId, FileLoadingStatus>) {
+    let pending = 0;
+    let total = 0;
+    for (const status of statuses.values()) {
+      total++;
+      if (status === "loading") {
+        pending++;
+      }
+    }
+    return { pending, total };
+  }
+}

excalidraw-app/vite.config.mts

@@ -106,6 +106,10 @@ export default defineConfig(({ mode }) => {
             if (id.includes("@excalidraw/mermaid-to-excalidraw")) {
               return "mermaid-to-excalidraw";
             }
+
+            if (id.includes("@codemirror/") || id.includes("@lezer/")) {
+              return "codemirror.chunk";
+            }
           },
         },
       },
@@ -150,6 +154,11 @@ export default defineConfig(({ mode }) => {
             "**/locales/**",
             "service-worker.js",
             "**/*.chunk-*.js",
+            // CodeMirrorEditor can't be assigned a `.chunk` name via
+            // manualChunks because Rollup would hoist shared deps (React)
+            // via a static import from the main bundle, defeating lazy
+            // loading. So we exclude it by name instead.
+            "**/CodeMirrorEditor-*.js",
           ],
           runtimeCaching: [
             {
@@ -189,7 +198,7 @@ export default defineConfig(({ mode }) => {
               },
             },
             {
-              urlPattern: new RegExp(".chunk-.+.js"),
+              urlPattern: new RegExp("(.chunk-.+|CodeMirrorEditor-.+)\\.js"),
               handler: "CacheFirst",
               options: {
                 cacheName: "chunk",

packages/common/src/appEventBus.test.ts

@@ -0,0 +1,74 @@
+import { AppEventBus } from "./appEventBus";
+
+type TestEvents = {
+  initialize: [api: number];
+  pointerUp: [pointerId: string];
+  viewState: [zoom: number];
+};
+
+const behavior = {
+  initialize: { cardinality: "once", replay: "last" },
+  pointerUp: { cardinality: "many", replay: "none" },
+  viewState: { cardinality: "many", replay: "last" },
+} as const;
+
+const flushMicrotasks = async () => Promise.resolve();
+
+describe("AppEventBus", () => {
+  it("replays once events to late callback and Promise subscribers", async () => {
+    const bus = new AppEventBus<TestEvents, typeof behavior>(behavior);
+    bus.emit("initialize", 42);
+
+    const calls: number[] = [];
+    bus.on("initialize", (value) => {
+      calls.push(value);
+    });
+
+    expect(calls).toEqual([]);
+    await flushMicrotasks();
+    expect(calls).toEqual([42]);
+
+    await expect(bus.on("initialize")).resolves.toBe(42);
+  });
+
+  it("does not replay stream events to late subscribers", async () => {
+    const bus = new AppEventBus<TestEvents, typeof behavior>(behavior);
+    bus.emit("pointerUp", "first");
+
+    const calls: string[] = [];
+    bus.on("pointerUp", (pointerId) => {
+      calls.push(pointerId);
+    });
+
+    await flushMicrotasks();
+    expect(calls).toEqual([]);
+
+    bus.emit("pointerUp", "second");
+    expect(calls).toEqual(["second"]);
+  });
+
+  it("replays replay-last stream events and stays subscribed", async () => {
+    const bus = new AppEventBus<TestEvents, typeof behavior>(behavior);
+    bus.emit("viewState", 1);
+
+    const calls: number[] = [];
+    bus.on("viewState", (zoom) => {
+      calls.push(zoom);
+    });
+
+    await flushMicrotasks();
+    expect(calls).toEqual([1]);
+
+    bus.emit("viewState", 2);
+    expect(calls).toEqual([1, 2]);
+  });
+
+  it("throws when emitting a once event twice", () => {
+    const bus = new AppEventBus<TestEvents, typeof behavior>(behavior);
+    bus.emit("initialize", 1);
+
+    expect(() => {
+      bus.emit("initialize", 2);
+    }).toThrow('Event "initialize" can only be emitted once');
+  });
+});

packages/common/src/appEventBus.ts

@@ -0,0 +1,136 @@
+import type { UnsubscribeCallback } from "@excalidraw/excalidraw/types";
+
+import { Emitter } from "./emitter";
+import { isProdEnv } from "./utils";
+
+export type AppEventPayloadMap = Record<string, unknown[]>;
+
+export type AppEventBehavior = {
+  cardinality: "once" | "many";
+  replay: "none" | "last";
+};
+
+export type AppEventBehaviorMap<Events extends AppEventPayloadMap> = {
+  [K in keyof Events]: AppEventBehavior;
+};
+
+type AwaitableAppEventKeys<
+  Events extends AppEventPayloadMap,
+  Behavior extends AppEventBehaviorMap<Events>,
+> = {
+  [K in keyof Events]: Behavior[K]["cardinality"] extends "once"
+    ? Behavior[K]["replay"] extends "last"
+      ? K
+      : never
+    : never;
+}[keyof Events];
+
+type AppEventPromiseValue<Args extends any[]> = Args extends [infer Only]
+  ? Only
+  : Args;
+
+export class AppEventBus<
+  Events extends AppEventPayloadMap,
+  Behavior extends AppEventBehaviorMap<Events>,
+> {
+  private readonly emitters = new Map<keyof Events, Emitter<any>>();
+  private readonly lastPayload = new Map<keyof Events, any[]>();
+  private readonly emittedOnce = new Set<keyof Events>();
+
+  constructor(private readonly behavior: Behavior) {}
+
+  private getEmitter<K extends keyof Events>(name: K): Emitter<Events[K]> {
+    let emitter = this.emitters.get(name);
+    if (!emitter) {
+      emitter = new Emitter<any>();
+      this.emitters.set(name, emitter);
+    }
+    return emitter as Emitter<Events[K]>;
+  }
+
+  private toPromiseValue<Args extends any[]>(
+    args: Args,
+  ): AppEventPromiseValue<Args> {
+    return (args.length === 1 ? args[0] : args) as AppEventPromiseValue<Args>;
+  }
+
+  public on<K extends keyof Events>(
+    name: K,
+    callback: (...args: Events[K]) => void,
+  ): UnsubscribeCallback;
+  public on<K extends AwaitableAppEventKeys<Events, Behavior>>(
+    name: K,
+  ): Promise<AppEventPromiseValue<Events[K]>>;
+  public on<K extends keyof Events>(
+    name: K,
+    callback?: (...args: Events[K]) => void,
+  ): UnsubscribeCallback | Promise<AppEventPromiseValue<Events[K]>> {
+    const eventBehavior = this.behavior[name];
+    const cachedPayload = this.lastPayload.get(name) as Events[K] | undefined;
+
+    if (callback) {
+      if (eventBehavior.replay === "last" && cachedPayload) {
+        queueMicrotask(() => callback(...cachedPayload));
+
+        if (eventBehavior.cardinality === "once") {
+          return () => {};
+        }
+      }
+
+      return this.getEmitter(name).on(callback);
+    }
+
+    if (
+      eventBehavior.cardinality !== "once" ||
+      eventBehavior.replay !== "last"
+    ) {
+      throw new Error(`Event "${String(name)}" requires a callback`);
+    }
+
+    if (cachedPayload) {
+      return Promise.resolve(this.toPromiseValue(cachedPayload));
+    }
+
+    return new Promise<AppEventPromiseValue<Events[K]>>((resolve) => {
+      this.getEmitter(name).once((...args: Events[K]) => {
+        resolve(this.toPromiseValue(args));
+      });
+    });
+  }
+
+  public emit<K extends keyof Events>(name: K, ...args: Events[K]) {
+    const eventBehavior = this.behavior[name];
+
+    if (!isProdEnv()) {
+      if (eventBehavior.cardinality === "once") {
+        if (this.emittedOnce.has(name)) {
+          throw new Error(`Event "${String(name)}" can only be emitted once`);
+        }
+        this.emittedOnce.add(name);
+      }
+    }
+
+    if (eventBehavior.replay === "last") {
+      this.lastPayload.set(name, args);
+    }
+
+    try {
+      this.getEmitter(name).trigger(...args);
+    } finally {
+      if (eventBehavior.cardinality === "once") {
+        this.getEmitter(name).clear();
+      }
+    }
+  }
+
+  public clear() {
+    this.lastPayload.clear();
+    this.emittedOnce.clear();
+
+    for (const emitter of this.emitters.values()) {
+      emitter.clear();
+    }
+
+    this.emitters.clear();
+  }
+}

packages/common/src/index.ts

@@ -11,5 +11,7 @@ export * from "./random";
 export * from "./url";
 export * from "./utils";
 export * from "./emitter";
+export * from "./appEventBus";
 export * from "./editorInterface";
+export * from "./versionedSnapshotStore";
 export { Debug } from "../debug";

packages/common/src/utils.test.ts

@@ -3,6 +3,12 @@ import {
   mapFind,
   reduceToCommonValue,
 } from "@excalidraw/common";
+import { vi } from "vitest";
+
+// Import directly to avoid the @excalidraw/common throttleRAF mock from setupTests.ts.
+import { throttleRAF } from "./utils";
+
+type RafCallback = FrameRequestCallback;
 
 describe("@excalidraw/common/utils", () => {
   describe("isTransparent()", () => {
@@ -79,4 +85,87 @@ describe("@excalidraw/common/utils", () => {
       expect(mapFind([1, 2], () => null)).toBe(undefined);
     });
   });
+
+  describe("throttleRAF()", () => {
+    let frameCallbacks: Map<number, RafCallback>;
+    let nextFrameId: number;
+
+    const runScheduledFrame = (timestamp = 16) => {
+      const callbacks = [...frameCallbacks.values()];
+      frameCallbacks.clear();
+      callbacks.forEach((callback) => callback(timestamp));
+    };
+
+    beforeEach(() => {
+      frameCallbacks = new Map();
+      nextFrameId = 0;
+
+      vi.spyOn(window, "requestAnimationFrame").mockImplementation(
+        (callback) => {
+          const frameId = ++nextFrameId;
+          frameCallbacks.set(frameId, callback);
+          return frameId;
+        },
+      );
+
+      vi.spyOn(window, "cancelAnimationFrame").mockImplementation((frameId) => {
+        frameCallbacks.delete(frameId);
+      });
+    });
+
+    afterEach(() => {
+      vi.restoreAllMocks();
+    });
+
+    it("should invoke the callback with the last args from the same frame", () => {
+      const fn = vi.fn();
+      const throttled = throttleRAF(fn);
+
+      throttled("first", 1);
+      throttled("second", 2);
+      throttled("last", 3);
+
+      expect(fn).not.toHaveBeenCalled();
+      expect(window.requestAnimationFrame).toHaveBeenCalledTimes(1);
+
+      runScheduledFrame();
+
+      expect(fn).toHaveBeenCalledTimes(1);
+      expect(fn).toHaveBeenCalledWith("last", 3);
+    });
+
+    it("should flush the pending callback immediately", () => {
+      const fn = vi.fn();
+      const throttled = throttleRAF(fn);
+
+      throttled("first");
+      throttled("last");
+
+      throttled.flush();
+
+      expect(window.cancelAnimationFrame).toHaveBeenCalledTimes(1);
+      expect(fn).toHaveBeenCalledTimes(1);
+      expect(fn).toHaveBeenCalledWith("last");
+
+      runScheduledFrame();
+
+      expect(fn).toHaveBeenCalledTimes(1);
+    });
+
+    it("should cancel the pending callback", () => {
+      const fn = vi.fn();
+      const throttled = throttleRAF(fn);
+
+      throttled("first");
+      throttled("last");
+
+      throttled.cancel();
+
+      expect(window.cancelAnimationFrame).toHaveBeenCalledTimes(1);
+
+      runScheduledFrame();
+
+      expect(fn).not.toHaveBeenCalled();
+    });
+  });
 });

packages/common/src/utils.ts

@@ -88,7 +88,8 @@ export const isWritableElement = (
     (target.type === "text" ||
       target.type === "number" ||
       target.type === "password" ||
-      target.type === "search"));
+      target.type === "search")) ||
+  (target instanceof HTMLElement && target.closest(".cm-editor") !== null);
 
 export const getFontFamilyString = ({
   fontFamily,
@@ -150,38 +151,27 @@ export const debounce = <T extends any[]>(
   return ret;
 };
 
-// throttle callback to execute once per animation frame
-export const throttleRAF = <T extends any[]>(
-  fn: (...args: T) => void,
-  opts?: { trailing?: boolean },
-) => {
+// throttle callback to execute once per animation frame using the latest args
+export const throttleRAF = <T extends any[]>(fn: (...args: T) => void) => {
   let timerId: number | null = null;
   let lastArgs: T | null = null;
-  let lastArgsTrailing: T | null = null;
 
-  const scheduleFunc = (args: T) => {
+  const scheduleFunc = () => {
     timerId = window.requestAnimationFrame(() => {
       timerId = null;
-      fn(...args);
+      const args = lastArgs;
       lastArgs = null;
-      if (lastArgsTrailing) {
-        lastArgs = lastArgsTrailing;
-        lastArgsTrailing = null;
-        scheduleFunc(lastArgs);
+
+      if (args) {
+        fn(...args);
       }
     });
   };
 
   const ret = (...args: T) => {
-    if (isTestEnv()) {
-      fn(...args);
-      return;
-    }
     lastArgs = args;
     if (timerId === null) {
-      scheduleFunc(lastArgs);
-    } else if (opts?.trailing) {
-      lastArgsTrailing = args;
+      scheduleFunc();
     }
   };
   ret.flush = () => {
@@ -190,12 +180,12 @@ export const throttleRAF = <T extends any[]>(
       timerId = null;
     }
     if (lastArgs) {
-      fn(...(lastArgsTrailing || lastArgs));
-      lastArgs = lastArgsTrailing = null;
+      fn(...lastArgs);
+      lastArgs = null;
     }
   };
   ret.cancel = () => {
-    lastArgs = lastArgsTrailing = null;
+    lastArgs = null;
     if (timerId !== null) {
       cancelAnimationFrame(timerId);
       timerId = null;

packages/common/src/versionedSnapshotStore.ts

@@ -0,0 +1,70 @@
+export type VersionedSnapshot<T> = Readonly<{
+  version: number;
+  value: T;
+}>;
+
+export class VersionedSnapshotStore<T> {
+  private version = 0;
+  private value: T;
+  private readonly waiters = new Set<
+    (snapshot: VersionedSnapshot<T>) => void
+  >();
+  private readonly subscribers = new Set<
+    (snapshot: VersionedSnapshot<T>) => void
+  >();
+
+  constructor(
+    initialValue: T,
+    private readonly isEqual: (prev: T, next: T) => boolean = Object.is,
+  ) {
+    this.value = initialValue;
+  }
+
+  public getSnapshot(): VersionedSnapshot<T> {
+    return { version: this.version, value: this.value };
+  }
+
+  public set(nextValue: T): boolean {
+    if (this.isEqual(this.value, nextValue)) {
+      return false;
+    }
+
+    this.value = nextValue;
+    this.version += 1;
+
+    const snapshot = this.getSnapshot();
+
+    for (const subscriber of this.subscribers) {
+      subscriber(snapshot);
+    }
+    for (const waiter of this.waiters) {
+      waiter(snapshot);
+    }
+    this.waiters.clear();
+
+    return true;
+  }
+
+  public update(updater: (prev: T) => T): boolean {
+    return this.set(updater(this.value));
+  }
+
+  public subscribe(
+    subscriber: (snapshot: VersionedSnapshot<T>) => void,
+  ): () => void {
+    this.subscribers.add(subscriber);
+    return () => {
+      this.subscribers.delete(subscriber);
+    };
+  }
+
+  public pull(sinceVersion = -1): Promise<VersionedSnapshot<T>> {
+    if (this.version !== sinceVersion) {
+      return Promise.resolve(this.getSnapshot());
+    }
+
+    return new Promise((resolve) => {
+      this.waiters.add(resolve);
+    });
+  }
+}

packages/element/src/arrowheads.ts

@@ -0,0 +1,32 @@
+import type { Arrowhead, AnyArrowhead } from "./types";
+
+export const normalizeArrowhead = (
+  arrowhead: AnyArrowhead | null | undefined,
+): Arrowhead | null => {
+  switch (arrowhead) {
+    case undefined:
+    case null:
+      return null;
+    case "dot":
+      return "circle";
+    case "crowfoot_one":
+      return "cardinality_one";
+    case "crowfoot_many":
+      return "cardinality_many";
+    case "crowfoot_one_or_many":
+      return "cardinality_one_or_many";
+    default:
+      return arrowhead;
+  }
+};
+
+export const getArrowheadForPicker = (
+  arrowhead: AnyArrowhead | null | undefined,
+): Arrowhead | null => {
+  const normalizedArrowhead = normalizeArrowhead(arrowhead);
+  if (normalizedArrowhead === null) {
+    return null;
+  }
+
+  return normalizedArrowhead;
+};

packages/element/src/bounds.ts

@@ -709,6 +709,9 @@ const getFreeDrawElementAbsoluteCoords = (
   return [x1, y1, x2, y2, (x1 + x2) / 2, (y1 + y2) / 2];
 };
 
+const CARDINALITY_MARKER_SIZE = 20;
+const CROWFOOT_ARROWHEAD_SIZE = 15;
+
 /** @returns number in pixels */
 export const getArrowheadSize = (arrowhead: Arrowhead): number => {
   switch (arrowhead) {
@@ -717,10 +720,14 @@ export const getArrowheadSize = (arrowhead: Arrowhead): number => {
     case "diamond":
     case "diamond_outline":
       return 12;
-    case "crowfoot_many":
-    case "crowfoot_one":
-    case "crowfoot_one_or_many":
-      return 20;
+    case "cardinality_many":
+    case "cardinality_one_or_many":
+    case "cardinality_zero_or_many":
+      return CROWFOOT_ARROWHEAD_SIZE;
+    case "cardinality_one":
+    case "cardinality_exactly_one":
+    case "cardinality_zero_or_one":
+      return CARDINALITY_MARKER_SIZE;
     default:
       return 15;
   }
@@ -743,7 +750,12 @@ export const getArrowheadPoints = (
   shape: Drawable[],
   position: "start" | "end",
   arrowhead: Arrowhead,
+  offsetMultiplier = 0,
 ) => {
+  if (arrowhead === null) {
+    return null;
+  }
+
   if (shape.length < 1) {
     return null;
   }
@@ -824,29 +836,30 @@ export const getArrowheadPoints = (
   const lengthMultiplier =
     arrowhead === "diamond" || arrowhead === "diamond_outline" ? 0.25 : 0.5;
   const minSize = Math.min(size, length * lengthMultiplier);
-  const xs = x2 - nx * minSize;
-  const ys = y2 - ny * minSize;
+  const tx = x2 - nx * minSize * offsetMultiplier;
+  const ty = y2 - ny * minSize * offsetMultiplier;
+  const xs = tx - nx * minSize;
+  const ys = ty - ny * minSize;
 
-  if (
-    arrowhead === "dot" ||
-    arrowhead === "circle" ||
-    arrowhead === "circle_outline"
-  ) {
-    const diameter = Math.hypot(ys - y2, xs - x2) + element.strokeWidth - 2;
-    return [x2, y2, diameter];
+  if (arrowhead === "circle" || arrowhead === "circle_outline") {
+    const diameter = Math.hypot(ys - ty, xs - tx) + element.strokeWidth - 2;
+    return [tx, ty, diameter];
   }
 
   const angle = getArrowheadAngle(arrowhead);
 
-  if (arrowhead === "crowfoot_many" || arrowhead === "crowfoot_one_or_many") {
+  if (
+    arrowhead === "cardinality_many" ||
+    arrowhead === "cardinality_one_or_many"
+  ) {
     // swap (xs, ys) with (x2, y2)
     const [x3, y3] = pointRotateRads(
-      pointFrom(x2, y2),
+      pointFrom(tx, ty),
       pointFrom(xs, ys),
       degreesToRadians(-angle as Degrees),
     );
     const [x4, y4] = pointRotateRads(
-      pointFrom(x2, y2),
+      pointFrom(tx, ty),
       pointFrom(xs, ys),
       degreesToRadians(angle),
     );
@@ -856,12 +869,12 @@ export const getArrowheadPoints = (
   // Return points
   const [x3, y3] = pointRotateRads(
     pointFrom(xs, ys),
-    pointFrom(x2, y2),
+    pointFrom(tx, ty),
     ((-angle * Math.PI) / 180) as Radians,
   );
   const [x4, y4] = pointRotateRads(
     pointFrom(xs, ys),
-    pointFrom(x2, y2),
+    pointFrom(tx, ty),
     degreesToRadians(angle),
   );
 
@@ -874,9 +887,9 @@ export const getArrowheadPoints = (
       const [px, py] = element.points.length > 1 ? element.points[1] : [0, 0];
 
       [ox, oy] = pointRotateRads(
-        pointFrom(x2 + minSize * 2, y2),
-        pointFrom(x2, y2),
-        Math.atan2(py - y2, px - x2) as Radians,
+        pointFrom(tx + minSize * 2, ty),
+        pointFrom(tx, ty),
+        Math.atan2(py - ty, px - tx) as Radians,
       );
     } else {
       const [px, py] =
@@ -885,16 +898,16 @@ export const getArrowheadPoints = (
           : [0, 0];
 
       [ox, oy] = pointRotateRads(
-        pointFrom(x2 - minSize * 2, y2),
-        pointFrom(x2, y2),
-        Math.atan2(y2 - py, x2 - px) as Radians,
+        pointFrom(tx - minSize * 2, ty),
+        pointFrom(tx, ty),
+        Math.atan2(ty - py, tx - px) as Radians,
       );
     }
 
-    return [x2, y2, x3, y3, ox, oy, x4, y4];
+    return [tx, ty, x3, y3, ox, oy, x4, y4];
   }
 
-  return [x2, y2, x3, y3, x4, y4];
+  return [tx, ty, x3, y3, x4, y4];
 };
 
 // TODO reuse shape.ts

packages/element/src/frame.ts

@@ -872,6 +872,19 @@ export const shouldApplyFrameClip = (
     return true;
   }
 
+  // Elements that belong to a frame should still render through that frame's
+  // clip, even when fully outside the frame bounds (e.g. generated content).
+  if (
+    !appState.selectedElementsAreBeingDragged &&
+    element.frameId === frame.id
+  ) {
+    for (const groupId of element.groupIds) {
+      checkedGroups?.set(groupId, true);
+    }
+
+    return true;
+  }
+
   // if an element is outside the frame, but is part of a group that has some elements
   // "in" the frame, we should clip the element
   if (

packages/element/src/index.ts

@@ -99,3 +99,4 @@ export * from "./typeChecks";
 export * from "./utils";
 export * from "./zindex";
 export * from "./arrows/helpers";
+export * from "./arrowheads";

packages/element/src/shape.ts

@@ -69,10 +69,10 @@ import type {
   NonDeletedExcalidrawElement,
   ExcalidrawSelectionElement,
   ExcalidrawLinearElement,
-  Arrowhead,
   ExcalidrawFreeDrawElement,
   ElementsMap,
   ExcalidrawLineElement,
+  Arrowhead,
 } from "./types";
 
 import type { Drawable, Options } from "roughjs/bin/core";
@@ -296,6 +296,82 @@ const modifyIframeLikeForRoughOptions = (
   return element;
 };
 
+const generateArrowheadCardinalityOne = (
+  generator: RoughGenerator,
+  arrowheadPoints: number[] | null,
+  lineOptions: Options,
+) => {
+  if (arrowheadPoints === null) {
+    return [];
+  }
+
+  const [, , x3, y3, x4, y4] = arrowheadPoints;
+
+  return [generator.line(x3, y3, x4, y4, lineOptions)];
+};
+
+const generateArrowheadLinesToTip = (
+  generator: RoughGenerator,
+  arrowheadPoints: number[] | null,
+  lineOptions: Options,
+) => {
+  if (arrowheadPoints === null) {
+    return [];
+  }
+
+  const [x2, y2, x3, y3, x4, y4] = arrowheadPoints;
+
+  return [
+    generator.line(x3, y3, x2, y2, lineOptions),
+    generator.line(x4, y4, x2, y2, lineOptions),
+  ];
+};
+
+const getArrowheadLineOptions = (
+  element: ExcalidrawLinearElement,
+  options: Options,
+) => {
+  const lineOptions = { ...options };
+
+  if (element.strokeStyle === "dotted") {
+    // for dotted arrows caps, reduce gap to make it more legible
+    const dash = getDashArrayDotted(element.strokeWidth - 1);
+    lineOptions.strokeLineDash = [dash[0], dash[1] - 1];
+  } else {
+    // for solid/dashed, keep solid arrow cap
+    delete lineOptions.strokeLineDash;
+  }
+  lineOptions.roughness = Math.min(1, lineOptions.roughness || 0);
+
+  return lineOptions;
+};
+
+const generateArrowheadOutlineCircle = (
+  generator: RoughGenerator,
+  options: Options,
+  strokeColor: string,
+  arrowheadPoints: number[] | null,
+  fill: string,
+  diameterScale = 1,
+) => {
+  if (arrowheadPoints === null) {
+    return [];
+  }
+
+  const [x, y, diameter] = arrowheadPoints;
+  const circleOptions = {
+    ...options,
+    fill,
+    fillStyle: "solid" as const,
+    stroke: strokeColor,
+    roughness: Math.min(0.5, options.roughness || 0),
+  };
+
+  delete circleOptions.strokeLineDash;
+
+  return [generator.circle(x, y, diameter * diameterScale, circleOptions)];
+};
+
 const getArrowheadShapes = (
   element: ExcalidrawLinearElement,
   shape: Drawable[],
@@ -306,63 +382,54 @@ const getArrowheadShapes = (
   canvasBackgroundColor: string,
   isDarkMode: boolean,
 ) => {
-  const arrowheadPoints = getArrowheadPoints(
-    element,
-    shape,
-    position,
-    arrowhead,
-  );
-
-  if (arrowheadPoints === null) {
+  if (arrowhead === null) {
     return [];
   }
 
-  const generateCrowfootOne = (
-    arrowheadPoints: number[] | null,
-    options: Options,
-  ) => {
-    if (arrowheadPoints === null) {
-      return [];
-    }
-
-    const [, , x3, y3, x4, y4] = arrowheadPoints;
-
-    return [generator.line(x3, y3, x4, y4, options)];
-  };
-
   const strokeColor = isDarkMode
     ? applyDarkModeFilter(element.strokeColor)
     : element.strokeColor;
+  const backgroundFillColor = isDarkMode
+    ? applyDarkModeFilter(canvasBackgroundColor)
+    : canvasBackgroundColor;
+  const cardinalityOneOrManyOffset = -0.25;
+  const cardinalityZeroCircleScale = 0.8;
 
   switch (arrowhead) {
-    case "dot":
     case "circle":
     case "circle_outline": {
-      const [x, y, diameter] = arrowheadPoints;
-
-      // always use solid stroke for arrowhead
-      delete options.strokeLineDash;
-
-      return [
-        generator.circle(x, y, diameter, {
-          ...options,
-          fill:
-            arrowhead === "circle_outline"
-              ? canvasBackgroundColor
-              : strokeColor,
-
-          fillStyle: "solid",
-          stroke: strokeColor,
-          roughness: Math.min(0.5, options.roughness || 0),
-        }),
-      ];
+      return generateArrowheadOutlineCircle(
+        generator,
+        options,
+        strokeColor,
+        getArrowheadPoints(element, shape, position, arrowhead),
+        arrowhead === "circle_outline" ? backgroundFillColor : strokeColor,
+      );
     }
     case "triangle":
     case "triangle_outline": {
+      const arrowheadPoints = getArrowheadPoints(
+        element,
+        shape,
+        position,
+        arrowhead,
+      );
+
+      if (arrowheadPoints === null) {
+        return [];
+      }
+
       const [x, y, x2, y2, x3, y3] = arrowheadPoints;
+      const triangleOptions = {
+        ...options,
+        fill:
+          arrowhead === "triangle_outline" ? backgroundFillColor : strokeColor,
+        fillStyle: "solid" as const,
+        roughness: Math.min(1, options.roughness || 0),
+      };
 
       // always use solid stroke for arrowhead
-      delete options.strokeLineDash;
+      delete triangleOptions.strokeLineDash;
 
       return [
         generator.polygon(
@@ -372,24 +439,34 @@ const getArrowheadShapes = (
             [x3, y3],
             [x, y],
           ],
-          {
-            ...options,
-            fill:
-              arrowhead === "triangle_outline"
-                ? canvasBackgroundColor
-                : strokeColor,
-            fillStyle: "solid",
-            roughness: Math.min(1, options.roughness || 0),
-          },
+          triangleOptions,
         ),
       ];
     }
     case "diamond":
     case "diamond_outline": {
+      const arrowheadPoints = getArrowheadPoints(
+        element,
+        shape,
+        position,
+        arrowhead,
+      );
+
+      if (arrowheadPoints === null) {
+        return [];
+      }
+
       const [x, y, x2, y2, x3, y3, x4, y4] = arrowheadPoints;
+      const diamondOptions = {
+        ...options,
+        fill:
+          arrowhead === "diamond_outline" ? backgroundFillColor : strokeColor,
+        fillStyle: "solid" as const,
+        roughness: Math.min(1, options.roughness || 0),
+      };
 
       // always use solid stroke for arrowhead
-      delete options.strokeLineDash;
+      delete diamondOptions.strokeLineDash;
 
       return [
         generator.polygon(
@@ -400,46 +477,106 @@ const getArrowheadShapes = (
             [x4, y4],
             [x, y],
           ],
-          {
-            ...options,
-            fill:
-              arrowhead === "diamond_outline"
-                ? canvasBackgroundColor
-                : strokeColor,
-            fillStyle: "solid",
-            roughness: Math.min(1, options.roughness || 0),
-          },
+          diamondOptions,
+        ),
+      ];
+    }
+    case "cardinality_one":
+      return generateArrowheadCardinalityOne(
+        generator,
+        getArrowheadPoints(element, shape, position, arrowhead),
+        getArrowheadLineOptions(element, options),
+      );
+    case "cardinality_many":
+      return generateArrowheadLinesToTip(
+        generator,
+        getArrowheadPoints(element, shape, position, arrowhead),
+        getArrowheadLineOptions(element, options),
+      );
+    case "cardinality_one_or_many": {
+      const lineOptions = getArrowheadLineOptions(element, options);
+
+      return [
+        ...generateArrowheadLinesToTip(
+          generator,
+          getArrowheadPoints(element, shape, position, "cardinality_many"),
+          lineOptions,
+        ),
+        ...generateArrowheadCardinalityOne(
+          generator,
+          getArrowheadPoints(
+            element,
+            shape,
+            position,
+            "cardinality_one",
+            cardinalityOneOrManyOffset,
+          ),
+          lineOptions,
+        ),
+      ];
+    }
+    case "cardinality_exactly_one": {
+      const lineOptions = getArrowheadLineOptions(element, options);
+
+      return [
+        ...generateArrowheadCardinalityOne(
+          generator,
+          getArrowheadPoints(element, shape, position, "cardinality_one", -0.5),
+          lineOptions,
+        ),
+        ...generateArrowheadCardinalityOne(
+          generator,
+          getArrowheadPoints(element, shape, position, "cardinality_one"),
+          lineOptions,
+        ),
+      ];
+    }
+    case "cardinality_zero_or_one": {
+      const lineOptions = getArrowheadLineOptions(element, options);
+
+      return [
+        ...generateArrowheadOutlineCircle(
+          generator,
+          options,
+          strokeColor,
+          getArrowheadPoints(element, shape, position, "circle_outline", 1.5),
+          backgroundFillColor,
+          cardinalityZeroCircleScale,
+        ),
+        ...generateArrowheadCardinalityOne(
+          generator,
+          getArrowheadPoints(element, shape, position, "cardinality_one", -0.5),
+          lineOptions,
+        ),
+      ];
+    }
+    case "cardinality_zero_or_many": {
+      const lineOptions = getArrowheadLineOptions(element, options);
+
+      return [
+        ...generateArrowheadLinesToTip(
+          generator,
+          getArrowheadPoints(element, shape, position, "cardinality_many"),
+          lineOptions,
+        ),
+        ...generateArrowheadOutlineCircle(
+          generator,
+          options,
+          strokeColor,
+          getArrowheadPoints(element, shape, position, "circle_outline", 1.5),
+          backgroundFillColor,
+          cardinalityZeroCircleScale,
         ),
       ];
     }
-    case "crowfoot_one":
-      return generateCrowfootOne(arrowheadPoints, options);
     case "bar":
     case "arrow":
-    case "crowfoot_many":
-    case "crowfoot_one_or_many":
     default: {
-      const [x2, y2, x3, y3, x4, y4] = arrowheadPoints;
-
-      if (element.strokeStyle === "dotted") {
-        // for dotted arrows caps, reduce gap to make it more legible
-        const dash = getDashArrayDotted(element.strokeWidth - 1);
-        options.strokeLineDash = [dash[0], dash[1] - 1];
-      } else {
-        // for solid/dashed, keep solid arrow cap
-        delete options.strokeLineDash;
-      }
-      options.roughness = Math.min(1, options.roughness || 0);
-      return [
-        generator.line(x3, y3, x2, y2, options),
-        generator.line(x4, y4, x2, y2, options),
-        ...(arrowhead === "crowfoot_one_or_many"
-          ? generateCrowfootOne(
-              getArrowheadPoints(element, shape, position, "crowfoot_one"),
-              options,
-            )
-          : []),
-      ];
+      return generateArrowheadLinesToTip(
+        generator,
+        getArrowheadPoints(element, shape, position, arrowhead),
+        getArrowheadLineOptions(element, options),
+      );
     }
   }
 };

packages/element/src/types.ts

@@ -303,19 +303,32 @@ export type PointsPositionUpdates = Map<
   { point: LocalPoint; isDragging?: boolean }
 >;
 
+export type CardinalityArrowhead =
+  | "cardinality_one"
+  | "cardinality_many"
+  | "cardinality_one_or_many"
+  | "cardinality_exactly_one"
+  | "cardinality_zero_or_one"
+  | "cardinality_zero_or_many";
+
+export type ArrowheadLegacy =
+  | "dot"
+  | "crowfoot_one"
+  | "crowfoot_many"
+  | "crowfoot_one_or_many";
+
 export type Arrowhead =
   | "arrow"
   | "bar"
-  | "dot" // legacy. Do not use for new elements.
   | "circle"
   | "circle_outline"
   | "triangle"
   | "triangle_outline"
   | "diamond"
   | "diamond_outline"
-  | "crowfoot_one"
-  | "crowfoot_many"
-  | "crowfoot_one_or_many";
+  | CardinalityArrowhead;
+
+export type AnyArrowhead = Arrowhead | ArrowheadLegacy;
 
 export type ExcalidrawLinearElement = _ExcalidrawElementBase &
   Readonly<{

packages/element/tests/frame.test.tsx

@@ -2,6 +2,7 @@ import {
   convertToExcalidrawElements,
   Excalidraw,
 } from "@excalidraw/excalidraw";
+import { arrayToMap } from "@excalidraw/common";
 
 import { API } from "@excalidraw/excalidraw/tests/helpers/api";
 import { Keyboard, Pointer } from "@excalidraw/excalidraw/tests/helpers/ui";
@@ -10,6 +11,8 @@ import {
   render,
 } from "@excalidraw/excalidraw/tests/test-utils";
 
+import { shouldApplyFrameClip } from "../src/frame";
+
 import type { ExcalidrawElement } from "../src/types";
 
 const { h } = window;
@@ -561,3 +564,78 @@ describe("adding elements to frames", () => {
     });
   });
 });
+
+describe("frame clipping", () => {
+  const getAppStateForFrameClip = () =>
+    ({
+      frameRendering: {
+        enabled: true,
+        clip: true,
+      },
+      selectedElementsAreBeingDragged: false,
+      selectedElementIds: {},
+      frameToHighlight: null,
+      editingGroupId: null,
+    } as any);
+
+  it("clips a frame child even when fully outside the frame bounds", () => {
+    const frame = API.createElement({
+      type: "frame",
+      id: "frame",
+      x: 0,
+      y: 0,
+      width: 100,
+      height: 100,
+    });
+    const outsideChild = API.createElement({
+      type: "rectangle",
+      id: "outside-child",
+      x: 250,
+      y: 250,
+      width: 50,
+      height: 50,
+      frameId: frame.id,
+    });
+
+    const elementsMap = arrayToMap([outsideChild, frame]);
+
+    expect(
+      shouldApplyFrameClip(
+        outsideChild,
+        frame,
+        getAppStateForFrameClip(),
+        elementsMap,
+      ),
+    ).toBe(true);
+  });
+
+  it("does not clip an outside element that does not belong to the frame", () => {
+    const frame = API.createElement({
+      type: "frame",
+      id: "frame",
+      x: 0,
+      y: 0,
+      width: 100,
+      height: 100,
+    });
+    const outsideElement = API.createElement({
+      type: "rectangle",
+      id: "outside",
+      x: 250,
+      y: 250,
+      width: 50,
+      height: 50,
+    });
+
+    const elementsMap = arrayToMap([outsideElement, frame]);
+
+    expect(
+      shouldApplyFrameClip(
+        outsideElement,
+        frame,
+        getAppStateForFrameClip(),
+        elementsMap,
+      ),
+    ).toBe(false);
+  });
+});

packages/excalidraw/CHANGELOG.md

@@ -11,6 +11,87 @@ The change should be grouped under one of the below section and must contain PR
 Please add the latest change on the top under the correct section.
 -->
 
+## Unreleased
+
+## Excalidraw API
+
+### Breaking changes
+
+- Renamed the `excalidrawAPI` prop to `onExcalidrawAPI`.
+  - `onExcalidrawAPI` is now called on mount (instead of during constructor), and later on unmount (with `null` value). The API may be removed altogether in the future (you can use `onMount` & `onUmount` to manage the `ExcalidrawAPI` object (e.g. to cache it to a global state), already).
+
+### Features
+
+- Added `ExcalidrawAPI.isDestroyed` flag. Set to `true` once the editor unmounts. Calling any `get*` method, `onStateChange`, or `onEvent` on a destroyed API instance will throw in development and `console.error` in production. The `ExcalidrawAPI` will be reset to `null` on umount, but to be extra safe, you should check `ExcalidrawAPI.isDestroyed` before calling these methods to guard against subtle race conditions in your code.
+
+- Added `onMount`, `onInitialize`, and `onUnmount` props. `onMount` receives `{ excalidrawAPI, container }` once the editor root is mounted. `onInitialize` fires once the initial scene has loaded. `onUnmount` fires just before unmounting.
+
+- Same events are also accessible imperatively through `api.onEvent(...)`.
+
+  ```tsx
+  <Excalidraw
+    onExcalidrawAPI={(api) => {
+      api.onEvent("editor:mount", ({ excalidrawAPI, container }) => {
+        console.log(container);
+      });
+
+      api.onEvent("editor:initialize").then((readyApi) => {
+        readyApi.scrollToContent();
+      });
+    }}
+  />
+  ```
+
+  Note that in future releases, most, if not all, `excalidrawAPI.on*` subscriptions will be removed in favor of `excalidrawAPI.onEvent(name)`.
+
+- Also added `"editor:unmount"` lifecycle event, only accessible via `api.onEvent("editor:unmount")`.
+
+- Exported `<ExcalidrawAPIProvider/>`, `useExcalidrawAPI()`, `useAppStateValue(prop | props | selectorFunction)`, and `useOnExcalidrawStateChange(prop | props | selectorFunction, callback)` from the package. The imperative API also now exposes `onStateChange(prop | props | selectorFunction, callback?)`, and `onEvent(name, callback)`.
+
+  ```tsx
+  <ExcalidrawAPIProvider>
+    <Excalidraw />
+    <Logger />
+  </ExcalidrawAPIProvider>;
+
+  function Logger() {
+    // initially null before the ExcalidrawAPIProvider initializes ater
+    // <Excalidraw/> renders
+    // When <Excalidraw/> unmounts, is reset back to null
+    const api = useExcalidrawAPI();
+
+    useAppStateValue("viewModeEnabled", (viewModeEnabled) => {
+      console.log("view mode changed:", viewModeEnabled);
+    });
+
+    React.useEffect(() => {
+      if (api) {
+        console.log("editor instance id:", api.id);
+      }
+    }, [api]);
+
+    return null;
+  }
+  ```
+
+- Added `onExport` so host apps can delay JSON export until async work completes. The handler receives the export data plus an `AbortSignal`, and may return a `Promise` or an async generator that yields progress updates for the built-in toast UI.
+
+  ```tsx
+  <Excalidraw
+    onExport={async function* (_type, { files }, { signal }) {
+      yield { type: "progress", message: "Waiting for images..." };
+
+      await waitForImagesToLoad(files, signal);
+
+      if (signal.aborted) {
+        return;
+      }
+
+      yield { type: "progress", message: "Export ready", progress: 1 };
+    }}
+  />
+  ```
+
 ## Excalidraw Library
 
 ## 0.18.0 (2025-03-11)

packages/excalidraw/README.md

@@ -1,10 +1,10 @@
 # Excalidraw
 
-**Excalidraw** is exported as a component to be directly embedded in your project.
+**Excalidraw** is exported as a React component that you can embed directly in your app.
 
 ## Installation
 
-Use `npm` or `yarn` to install the package.
+Install the package together with its React peer dependencies.
 
 ```bash
 npm install react react-dom @excalidraw/excalidraw
@@ -12,34 +12,131 @@ npm install react react-dom @excalidraw/excalidraw
 yarn add react react-dom @excalidraw/excalidraw
 ```
 
-> **Note**: If you don't want to wait for the next stable release and try out the unreleased changes, use `@excalidraw/excalidraw@next`.
+> **Note**: If you want to try unreleased changes, use `@excalidraw/excalidraw@next`.
 
-#### Self-hosting fonts
+## Quick start
 
-By default, Excalidraw will try to download all the used fonts from the [CDN](https://esm.run/@excalidraw/excalidraw/dist/prod).
+The minimum working setup has two easy-to-miss requirements:
 
-For self-hosting purposes, you'll have to copy the content of the folder `node_modules/@excalidraw/excalidraw/dist/prod/fonts` to the path where your assets should be served from (i.e. `public/` directory in your project). In that case, you should also set `window.EXCALIDRAW_ASSET_PATH` to the very same path, i.e. `/` in case it's in the root:
+1. Import the package CSS:
 
-```js
-<script>window.EXCALIDRAW_ASSET_PATH = "/";</script>
+```ts
+import "@excalidraw/excalidraw/index.css";
 ```
 
-### Dimensions of Excalidraw
+2. Render Excalidraw inside a container with a non-zero height.
 
-Excalidraw takes _100%_ of `width` and `height` of the containing block so make sure the container in which you render Excalidraw has non zero dimensions.
+```tsx
+import { Excalidraw } from "@excalidraw/excalidraw";
+import "@excalidraw/excalidraw/index.css";
+
+export default function App() {
+  return (
+    <div style={{ height: "100vh" }}>
+      <Excalidraw />
+    </div>
+  );
+}
+```
+
+Excalidraw fills `100%` of the width and height of its parent. If the parent has no height, the canvas will not be visible.
+
+## Next.js / SSR frameworks
+
+Excalidraw should be rendered on the client. In SSR frameworks such as Next.js, use a client component and load it dynamically with SSR disabled.
+
+```tsx
+// app/components/ExcalidrawClient.tsx
+"use client";
+
+import { Excalidraw } from "@excalidraw/excalidraw";
+import "@excalidraw/excalidraw/index.css";
+
+export default function ExcalidrawClient() {
+  return (
+    <div style={{ height: "100vh" }}>
+      <Excalidraw />
+    </div>
+  );
+}
+```
+
+```tsx
+// app/page.tsx
+import dynamic from "next/dynamic";
+
+const ExcalidrawClient = dynamic(
+  () => import("./components/ExcalidrawClient"),
+  { ssr: false },
+);
+
+export default function Page() {
+  return <ExcalidrawClient />;
+}
+```
+
+See the local examples for complete setups:
+
+- [examples/with-nextjs](https://github.com/excalidraw/excalidraw/tree/master/examples/with-nextjs)
+- [examples/with-script-in-browser](https://github.com/excalidraw/excalidraw/tree/master/examples/with-script-in-browser)
+
+## LLM / agent tips
+
+If an LLM or coding agent is setting up Excalidraw, these shortcuts usually save more time than re-prompting:
+
+- Start with a plain `<Excalidraw />` in a `100vh` container. Add refs, `initialData`, persistence, or custom UI only after the base embed works.
+- If the canvas is blank, check the CSS import and parent height first. Those are the two most common integration failures.
+- In Next.js or other SSR frameworks, assume client-only rendering first. Use `"use client"` and `dynamic(..., { ssr: false })` before debugging hydration or `window is not defined` errors.
+- If imports or entrypoints are unclear, inspect `node_modules/@excalidraw/excalidraw/package.json`. The installed package exports are the source of truth.
+- Do not set `window.EXCALIDRAW_ASSET_PATH` unless you are intentionally self-hosting fonts/assets.
+- When docs and generated code drift, copy the nearest working example from this repo, especially `examples/with-nextjs` or `examples/with-script-in-browser`.
+
+## Migrating to `@excalidraw/excalidraw@0.18.x`
+
+Version `0.18.x` removes the old `types/`-prefixed deep import paths. If you were importing types from `@excalidraw/excalidraw/types/...`, switch to the new type-only subpaths below.
+
+| Old path | New path |
+| --- | --- |
+| `@excalidraw/excalidraw/types/data/transform.js` | `@excalidraw/excalidraw/element/transform` |
+| `@excalidraw/excalidraw/types/data/types.js` | `@excalidraw/excalidraw/data/types` |
+| `@excalidraw/excalidraw/types/element/types.js` | `@excalidraw/excalidraw/element/types` |
+| `@excalidraw/excalidraw/types/utility-types.js` | `@excalidraw/excalidraw/common/utility-types` |
+| `@excalidraw/excalidraw/types/types.js` | `@excalidraw/excalidraw/types` |
+
+Drop the `.js` extension. The new package `exports` map resolves these paths without it.
+
+These deep subpaths are for `import type` only. Runtime imports should come from the package root, plus `@excalidraw/excalidraw/index.css` for styles.
+
+For example:
+
+```ts
+import { exportToSvg } from "@excalidraw/excalidraw";
+```
+
+## Self-hosting fonts
+
+By default, Excalidraw downloads the fonts it needs from the [CDN](https://esm.run/@excalidraw/excalidraw/dist/prod).
+
+For self-hosting, copy the contents of `node_modules/@excalidraw/excalidraw/dist/prod/fonts` into the path where your app serves static assets, for example `public/`. Then set `window.EXCALIDRAW_ASSET_PATH` to that same path:
+
+```html
+<script>
+  window.EXCALIDRAW_ASSET_PATH = "/";
+</script>
+```
 
 ## Demo
 
-Go to [CodeSandbox](https://codesandbox.io/p/sandbox/github/excalidraw/excalidraw/tree/master/examples/with-script-in-browser) example.
+Try the [CodeSandbox example](https://codesandbox.io/p/sandbox/github/excalidraw/excalidraw/tree/master/examples/with-script-in-browser).
 
 ## Integration
 
-Head over to the [docs](https://docs.excalidraw.com/docs/@excalidraw/excalidraw/integration).
+Read the [integration docs](https://docs.excalidraw.com/docs/@excalidraw/excalidraw/integration).
 
 ## API
 
-Head over to the [docs](https://docs.excalidraw.com/docs/@excalidraw/excalidraw/api).
+Read the [API docs](https://docs.excalidraw.com/docs/@excalidraw/excalidraw/api).
 
 ## Contributing
 
-Head over to the [docs](https://docs.excalidraw.com/docs/@excalidraw/excalidraw/contributing).
+Read the [contributing docs](https://docs.excalidraw.com/docs/@excalidraw/excalidraw/contributing).

packages/excalidraw/actions/actionDeleteSelected.tsx

@@ -30,7 +30,7 @@ import { getSelectedElements, isSomeElementSelected } from "../scene";
 import { TrashIcon } from "../components/icons";
 import { ToolButton } from "../components/ToolButton";
 
-import { useStylesPanelMode } from "..";
+import { useStylesPanelMode } from "../components/App";
 
 import { register } from "./register";
 

packages/excalidraw/actions/actionDuplicateSelection.tsx

@@ -27,7 +27,7 @@ import { t } from "../i18n";
 import { isSomeElementSelected } from "../scene";
 import { getShortcutKey } from "../shortcut";
 
-import { useStylesPanelMode } from "..";
+import { useStylesPanelMode } from "../components/App";
 
 import { register } from "./register";
 

packages/excalidraw/actions/actionExport.tsx

@@ -9,18 +9,20 @@ import { getNonDeletedElements } from "@excalidraw/element";
 
 import { CaptureUpdateAction } from "@excalidraw/element";
 
-import type { Theme } from "@excalidraw/element/types";
+import type { ExcalidrawElement, Theme } from "@excalidraw/element/types";
 
 import { useEditorInterface } from "../components/App";
 import { CheckboxItem } from "../components/CheckboxItem";
 import { DarkModeToggle } from "../components/DarkModeToggle";
 import { ProjectName } from "../components/ProjectName";
+import { Toast } from "../components/Toast";
 import { ToolButton } from "../components/ToolButton";
 import { Tooltip } from "../components/Tooltip";
 import { ExportIcon, questionCircle, saveAs } from "../components/icons";
 import { loadFromJSON, saveAsJSON } from "../data";
 import { isImageFileHandle } from "../data/blob";
 import { nativeFileSystemSupported } from "../data/filesystem";
+
 import { resaveAsImageWithScene } from "../data/resave";
 
 import { t } from "../i18n";
@@ -31,7 +33,15 @@ import "../components/ToolIcon.scss";
 
 import { register } from "./register";
 
-import type { AppState } from "../types";
+import type { JSONExportData } from "../data/json";
+
+import type {
+  AppClassProperties,
+  AppState,
+  BinaryFiles,
+  ExcalidrawProps,
+  OnExportProgress,
+} from "../types";
 
 export const actionChangeProjectName = register<AppState["name"]>({
   name: "changeProjectName",
@@ -150,6 +160,143 @@ export const actionChangeExportEmbedScene = register<
   ),
 });
 
+// ---------------------------------------------------------------------------
+// onExport interception helpers
+// ---------------------------------------------------------------------------
+
+let onExportInProgress = false;
+
+const onProgressToast = (
+  app: AppClassProperties,
+  progress: {
+    message?: OnExportProgress["message"];
+    progress?: number | null;
+  },
+) => {
+  const message = progress.message ?? t("progressDialog.defaultMessage");
+  app.setAppState({
+    toast: {
+      message:
+        progress.progress != null ? (
+          <>
+            {message}
+            <Toast.ProgressBar progress={progress.progress} />
+          </>
+        ) : (
+          message
+        ),
+      duration: Infinity,
+    },
+  });
+};
+
+/** awaits host app's onExport result, and renders progress to the UI */
+async function handleOnExportResult(
+  onExportResult: ReturnType<NonNullable<ExcalidrawProps["onExport"]>>,
+  opts: {
+    signal: AbortSignal;
+    app: AppClassProperties;
+  },
+): Promise<void> {
+  if (opts.app.state.isLoading) {
+    onProgressToast(opts.app, { progress: null });
+    await opts.app.onStateChange({ predicate: (state) => !state.isLoading });
+  }
+
+  if (
+    onExportResult != null &&
+    typeof onExportResult === "object" &&
+    Symbol.asyncIterator in onExportResult
+  ) {
+    for await (const value of onExportResult) {
+      if (opts.signal.aborted) {
+        onExportResult.return();
+        return;
+      }
+      if (value.type === "progress") {
+        onProgressToast(opts.app, {
+          message: value.message,
+          progress: value.progress ?? null,
+        });
+      } else if (value.type === "done") {
+        return;
+      }
+    }
+
+    // Generator completed without explicit "done" message
+    return;
+  }
+
+  if (onExportResult instanceof Promise) {
+    onProgressToast(opts.app, { progress: null });
+    await onExportResult;
+  }
+}
+
+function prepareDataForJSONExport(
+  elements: readonly ExcalidrawElement[],
+  appState: AppState,
+  files: BinaryFiles,
+  app: AppClassProperties,
+): { abortController: AbortController; data: Promise<JSONExportData> } {
+  const abortController = new AbortController();
+  const signal = abortController.signal;
+
+  const dataPromise = new Promise<JSONExportData>(async (resolve) => {
+    try {
+      if (app.props.onExport) {
+        await handleOnExportResult(
+          app.props.onExport(
+            "json",
+            {
+              elements,
+              appState,
+              files,
+            },
+            {
+              signal,
+            },
+          ),
+          {
+            app,
+            signal,
+          },
+        );
+      }
+    } catch (error: any) {
+      if (error?.name === "AbortError") {
+        // if abort error, assume it's a reaction on the signal being aborted
+        console.warn(
+          `onExport() aborted by host app (signal aborted: ${signal.aborted})`,
+        );
+      } else {
+        // non-abort error
+        //
+        console.error("Error during props.onExport() handling", error);
+      }
+
+      // either way, we currently don't allow host apps to cancel save actions
+      // so we resolve to orig data
+    }
+
+    resolve({
+      elements,
+      appState,
+      // return latest files in case they finished loading during onExport
+      files: app.files,
+    });
+  });
+
+  return {
+    abortController,
+    data: dataPromise,
+  };
+}
+
+// ---------------------------------------------------------------------------
+// Save actions
+// ---------------------------------------------------------------------------
+
 export const actionSaveToActiveFile = register({
   name: "saveToActiveFile",
   label: "buttons.save",
@@ -163,42 +310,62 @@ export const actionSaveToActiveFile = register({
     );
   },
   perform: async (elements, appState, value, app) => {
-    const fileHandleExists = !!appState.fileHandle;
+    if (onExportInProgress) {
+      return false;
+    }
+    onExportInProgress = true;
+
+    const previousFileHandle = appState.fileHandle;
+    const filename = app.getName();
+
+    const { abortController, data: exportedDataPromise } =
+      prepareDataForJSONExport(elements, appState, app.files, app);
 
     try {
-      const { fileHandle } = isImageFileHandle(appState.fileHandle)
+      const { fileHandle } = isImageFileHandle(previousFileHandle)
         ? await resaveAsImageWithScene(
-            elements,
-            appState,
-            app.files,
-            app.getName(),
+            exportedDataPromise,
+            previousFileHandle,
+            filename,
           )
-        : await saveAsJSON(elements, appState, app.files, app.getName());
+        : await saveAsJSON({
+            data: exportedDataPromise,
+            filename,
+            fileHandle: previousFileHandle,
+          });
 
       return {
-        captureUpdate: CaptureUpdateAction.EVENTUALLY,
+        captureUpdate: CaptureUpdateAction.NEVER,
         appState: {
-          ...appState,
           fileHandle,
-          toast: fileHandleExists
-            ? {
-                message: fileHandle?.name
-                  ? t("toast.fileSavedToFilename").replace(
-                      "{filename}",
-                      `"${fileHandle.name}"`,
-                    )
-                  : t("toast.fileSaved"),
-              }
-            : null,
+          toast: {
+            message:
+              previousFileHandle && fileHandle?.name
+                ? t("toast.fileSavedToFilename").replace(
+                    "{filename}",
+                    `"${fileHandle.name}"`,
+                  )
+                : t("toast.fileSaved"),
+            duration: 1500,
+          },
         },
       };
     } catch (error: any) {
+      abortController.abort();
+
       if (error?.name !== "AbortError") {
         console.error(error);
       } else {
         console.warn(error);
       }
-      return { captureUpdate: CaptureUpdateAction.EVENTUALLY };
+      return {
+        captureUpdate: CaptureUpdateAction.NEVER,
+        appState: {
+          toast: null,
+        },
+      };
+    } finally {
+      onExportInProgress = false;
     }
   },
   keyTest: (event) =>
@@ -212,36 +379,50 @@ export const actionSaveFileToDisk = register({
   viewMode: true,
   trackEvent: { category: "export" },
   perform: async (elements, appState, value, app) => {
+    if (onExportInProgress) {
+      return false;
+    }
+    onExportInProgress = true;
+
+    const { abortController, data: exportedDataPromise } =
+      prepareDataForJSONExport(elements, appState, app.files, app);
+
     try {
-      const { fileHandle } = await saveAsJSON(
-        elements,
-        {
-          ...appState,
-          fileHandle: null,
-        },
-        app.files,
-        app.getName(),
-      );
+      const { fileHandle: savedFileHandle } = await saveAsJSON({
+        data: exportedDataPromise,
+        filename: app.getName(),
+        fileHandle: null,
+      });
+
       return {
-        captureUpdate: CaptureUpdateAction.EVENTUALLY,
+        captureUpdate: CaptureUpdateAction.NEVER,
         appState: {
-          ...appState,
           openDialog: null,
-          fileHandle,
-          toast: { message: t("toast.fileSaved") },
+          fileHandle: savedFileHandle,
+          toast: { message: t("toast.fileSaved"), duration: 3000 },
         },
       };
     } catch (error: any) {
+      abortController.abort();
       if (error?.name !== "AbortError") {
         console.error(error);
       } else {
         console.warn(error);
       }
-      return { captureUpdate: CaptureUpdateAction.EVENTUALLY };
+      return {
+        captureUpdate: CaptureUpdateAction.NEVER,
+        appState: {
+          toast: null,
+        },
+      };
+    } finally {
+      onExportInProgress = false;
     }
   },
   keyTest: (event) =>
-    event.key === KEYS.S && event.shiftKey && event[KEYS.CTRL_OR_CMD],
+    event.key.toLowerCase() === KEYS.S &&
+    event.shiftKey &&
+    event[KEYS.CTRL_OR_CMD],
   PanelComponent: ({ updateData }) => (
     <ToolButton
       type="button"
@@ -300,7 +481,8 @@ export const actionExportWithDarkMode = register<
   name: "exportWithDarkMode",
   label: "imageExportDialog.label.darkMode",
   trackEvent: { category: "export", action: "toggleTheme" },
-  perform: (_elements, appState, value) => {
+  perform: (_elements, appState, value, app) => {
+    app.sessionExportThemeOverride = value ? THEME.DARK : THEME.LIGHT;
     return {
       appState: { ...appState, exportWithDarkMode: value },
       captureUpdate: CaptureUpdateAction.EVENTUALLY,

packages/excalidraw/actions/actionHistory.tsx

@@ -18,7 +18,7 @@ import { HistoryChangedEvent } from "../history";
 import { useEmitter } from "../hooks/useEmitter";
 import { t } from "../i18n";
 
-import { useStylesPanelMode } from "..";
+import { useStylesPanelMode } from "../components/App";
 
 import type { History } from "../history";
 import type { AppClassProperties, AppState } from "../types";

packages/excalidraw/actions/actionProperties.tsx

@@ -36,6 +36,7 @@ import {
 import { LinearElementEditor } from "@excalidraw/element";
 
 import { newElementWith } from "@excalidraw/element";
+import { getArrowheadForPicker } from "@excalidraw/element";
 
 import {
   getBoundTextElement,
@@ -124,9 +125,12 @@ import {
   sharpArrowIcon,
   roundArrowIcon,
   elbowArrowIcon,
-  ArrowheadCrowfootIcon,
-  ArrowheadCrowfootOneIcon,
-  ArrowheadCrowfootOneOrManyIcon,
+  ArrowheadCardinalityExactlyOneIcon,
+  ArrowheadCardinalityManyIcon,
+  ArrowheadCardinalityOneIcon,
+  ArrowheadCardinalityOneOrManyIcon,
+  ArrowheadCardinalityZeroOrManyIcon,
+  ArrowheadCardinalityZeroOrOneIcon,
 } from "../components/icons";
 
 import { Fonts } from "../fonts";
@@ -1550,80 +1554,117 @@ export const actionChangeRoundness = register<"sharp" | "round">({
 });
 
 const getArrowheadOptions = (flip: boolean) => {
-  return [
-    {
-      value: null,
-      text: t("labels.arrowhead_none"),
-      keyBinding: "q",
-      icon: <ArrowheadNoneIcon flip={flip} />,
-    },
-    {
-      value: "arrow",
-      text: t("labels.arrowhead_arrow"),
-      keyBinding: "w",
-      icon: <ArrowheadArrowIcon flip={flip} />,
-    },
-    {
-      value: "triangle",
-      text: t("labels.arrowhead_triangle"),
-      icon: <ArrowheadTriangleIcon flip={flip} />,
-      keyBinding: "e",
-    },
-    {
-      value: "triangle_outline",
-      text: t("labels.arrowhead_triangle_outline"),
-      icon: <ArrowheadTriangleOutlineIcon flip={flip} />,
-      keyBinding: "r",
-    },
-    {
-      value: "circle",
-      text: t("labels.arrowhead_circle"),
-      keyBinding: "a",
-      icon: <ArrowheadCircleIcon flip={flip} />,
-    },
-    {
-      value: "circle_outline",
-      text: t("labels.arrowhead_circle_outline"),
-      keyBinding: "s",
-      icon: <ArrowheadCircleOutlineIcon flip={flip} />,
-    },
-    {
-      value: "diamond",
-      text: t("labels.arrowhead_diamond"),
-      icon: <ArrowheadDiamondIcon flip={flip} />,
-      keyBinding: "d",
-    },
-    {
-      value: "diamond_outline",
-      text: t("labels.arrowhead_diamond_outline"),
-      icon: <ArrowheadDiamondOutlineIcon flip={flip} />,
-      keyBinding: "f",
-    },
-    {
-      value: "bar",
-      text: t("labels.arrowhead_bar"),
-      keyBinding: "z",
-      icon: <ArrowheadBarIcon flip={flip} />,
-    },
-    {
-      value: "crowfoot_one",
-      text: t("labels.arrowhead_crowfoot_one"),
-      icon: <ArrowheadCrowfootOneIcon flip={flip} />,
-      keyBinding: "x",
-    },
-    {
-      value: "crowfoot_many",
-      text: t("labels.arrowhead_crowfoot_many"),
-      icon: <ArrowheadCrowfootIcon flip={flip} />,
-      keyBinding: "c",
-    },
-    {
-      value: "crowfoot_one_or_many",
-      text: t("labels.arrowhead_crowfoot_one_or_many"),
-      icon: <ArrowheadCrowfootOneOrManyIcon flip={flip} />,
-      keyBinding: "v",
-    },
-  ] as const;
+  return {
+    visibleSections: [
+      {
+        name: "default",
+        options: [
+          {
+            value: null,
+            text: t("labels.arrowhead_none"),
+            keyBinding: "q",
+            icon: <ArrowheadNoneIcon flip={flip} />,
+          },
+          {
+            value: "arrow",
+            text: t("labels.arrowhead_arrow"),
+            keyBinding: "w",
+            icon: <ArrowheadArrowIcon flip={flip} />,
+          },
+          {
+            value: "triangle",
+            text: t("labels.arrowhead_triangle"),
+            icon: <ArrowheadTriangleIcon flip={flip} />,
+            keyBinding: "e",
+          },
+          {
+            value: "triangle_outline",
+            text: t("labels.arrowhead_triangle_outline"),
+            icon: <ArrowheadTriangleOutlineIcon flip={flip} />,
+            keyBinding: "r",
+          },
+        ],
+      },
+    ],
+    hiddenSections: [
+      {
+        name: "default",
+        options: [
+          {
+            value: "circle",
+            text: t("labels.arrowhead_circle"),
+            keyBinding: "a",
+            icon: <ArrowheadCircleIcon flip={flip} />,
+          },
+          {
+            value: "circle_outline",
+            text: t("labels.arrowhead_circle_outline"),
+            keyBinding: "s",
+            icon: <ArrowheadCircleOutlineIcon flip={flip} />,
+          },
+          {
+            value: "diamond",
+            text: t("labels.arrowhead_diamond"),
+            icon: <ArrowheadDiamondIcon flip={flip} />,
+            keyBinding: "d",
+          },
+          {
+            value: "diamond_outline",
+            text: t("labels.arrowhead_diamond_outline"),
+            icon: <ArrowheadDiamondOutlineIcon flip={flip} />,
+            keyBinding: "f",
+          },
+          {
+            value: "bar",
+            text: t("labels.arrowhead_bar"),
+            keyBinding: "z",
+            icon: <ArrowheadBarIcon flip={flip} />,
+          },
+        ],
+      },
+      {
+        name: t("labels.cardinality"),
+        options: [
+          {
+            value: "cardinality_one",
+            text: t("labels.arrowhead_cardinality_one"),
+            icon: <ArrowheadCardinalityOneIcon flip={flip} />,
+            keyBinding: "x",
+          },
+          {
+            value: "cardinality_many",
+            text: t("labels.arrowhead_cardinality_many"),
+            icon: <ArrowheadCardinalityManyIcon flip={flip} />,
+            keyBinding: "c",
+          },
+          {
+            value: "cardinality_one_or_many",
+            text: t("labels.arrowhead_cardinality_one_or_many"),
+            icon: <ArrowheadCardinalityOneOrManyIcon flip={flip} />,
+            keyBinding: "v",
+          },
+          {
+            value: "cardinality_exactly_one",
+            text: t("labels.arrowhead_cardinality_exactly_one"),
+            icon: <ArrowheadCardinalityExactlyOneIcon flip={flip} />,
+            keyBinding: null,
+          },
+          {
+            value: "cardinality_zero_or_one",
+            text: t("labels.arrowhead_cardinality_zero_or_one"),
+            icon: <ArrowheadCardinalityZeroOrOneIcon flip={flip} />,
+            keyBinding: null,
+          },
+          {
+            value: "cardinality_zero_or_many",
+            text: t("labels.arrowhead_cardinality_zero_or_many"),
+            icon: <ArrowheadCardinalityZeroOrManyIcon flip={flip} />,
+            keyBinding: null,
+          },
+        ],
+      },
+    ],
+  } as const;
 };
 
 export const actionChangeArrowhead = register<{
@@ -1667,45 +1708,52 @@ export const actionChangeArrowhead = register<{
   },
   PanelComponent: ({ elements, appState, updateData, app }) => {
     const isRTL = getLanguage().rtl;
+    const startArrowheadOptions = useMemo(
+      () => getArrowheadOptions(!isRTL),
+      [isRTL],
+    );
+    const endArrowheadOptions = useMemo(
+      () => getArrowheadOptions(!!isRTL),
+      [isRTL],
+    );
 
     return (
       <fieldset>
         <legend>{t("labels.arrowheads")}</legend>
         <div className="iconSelectList buttonList">
           <IconPicker
+            visibleSections={startArrowheadOptions.visibleSections}
+            hiddenSections={startArrowheadOptions.hiddenSections}
             label="arrowhead_start"
-            options={getArrowheadOptions(!isRTL)}
             value={getFormValue<Arrowhead | null>(
               elements,
               app,
               (element) =>
                 isLinearElement(element) && canHaveArrowheads(element.type)
-                  ? element.startArrowhead
+                  ? getArrowheadForPicker(element.startArrowhead)
                   : appState.currentItemStartArrowhead,
               true,
               (hasSelection) =>
                 hasSelection ? null : appState.currentItemStartArrowhead,
             )}
             onChange={(value) => updateData({ position: "start", type: value })}
-            numberOfOptionsToAlwaysShow={4}
           />
           <IconPicker
+            visibleSections={endArrowheadOptions.visibleSections}
+            hiddenSections={endArrowheadOptions.hiddenSections}
             label="arrowhead_end"
-            group="arrowheads"
-            options={getArrowheadOptions(!!isRTL)}
             value={getFormValue<Arrowhead | null>(
               elements,
               app,
               (element) =>
                 isLinearElement(element) && canHaveArrowheads(element.type)
-                  ? element.endArrowhead
+                  ? getArrowheadForPicker(element.endArrowhead)
                   : appState.currentItemEndArrowhead,
               true,
               (hasSelection) =>
                 hasSelection ? null : appState.currentItemEndArrowhead,
             )}
             onChange={(value) => updateData({ position: "end", type: value })}
-            numberOfOptionsToAlwaysShow={4}
           />
         </div>
       </fieldset>

packages/excalidraw/clipboard.ts

@@ -33,8 +33,6 @@ import {
   normalizeFile,
 } from "./data/blob";
 
-import type { FileSystemHandle } from "./data/filesystem";
-
 import type { BinaryFiles } from "./types";
 
 type ElementsClipboard = {
@@ -369,7 +367,7 @@ type AllowedParsedDataTransferItem =
       type: ValueOf<typeof IMAGE_MIME_TYPES>;
       kind: "file";
       file: File;
-      fileHandle: FileSystemHandle | null;
+      fileHandle: FileSystemFileHandle | null;
     }
   | { type: ValueOf<typeof STRING_MIME_TYPES>; kind: "string"; value: string };
 
@@ -378,7 +376,7 @@ type ParsedDataTransferItem =
       type: string;
       kind: "file";
       file: File;
-      fileHandle: FileSystemHandle | null;
+      fileHandle: FileSystemFileHandle | null;
     }
   | { type: string; kind: "string"; value: string };
 

packages/excalidraw/components/App.tsx

@@ -88,6 +88,7 @@ import {
   isShallowEqual,
   arrayToMap,
   applyDarkModeFilter,
+  AppEventBus,
   type EXPORT_IMAGE_TYPES,
   randomInteger,
   CLASSES,
@@ -448,7 +449,7 @@ import { StaticCanvas, InteractiveCanvas } from "./canvases";
 import NewElementCanvas from "./canvases/NewElementCanvas";
 import { isPointHittingLink } from "./hyperlink/helpers";
 import { MagicIcon, copyIcon, fullscreenIcon } from "./icons";
-import { Toast } from "./Toast";
+import { AppStateObserver, type OnStateChange } from "./AppStateObserver";
 
 import { findShapeByKey } from "./shapes";
 
@@ -464,7 +465,6 @@ import type {
 import type { ClipboardData, PastedMixedContent } from "../clipboard";
 import type { ExportedElements } from "../data";
 import type { ContextMenuItems } from "./ContextMenu";
-import type { FileSystemHandle } from "../data/filesystem";
 
 import type {
   AppClassProperties,
@@ -488,6 +488,7 @@ import type {
   UnsubscribeCallback,
   EmbedsValidationStatus,
   ElementsPendingErasure,
+  ExcalidrawImperativeAPIEventMap,
   GenerateDiagramToCode,
   NullableGridSize,
   Offsets,
@@ -513,6 +514,12 @@ const EditorInterfaceContext = React.createContext<EditorInterface>(
 );
 EditorInterfaceContext.displayName = "EditorInterfaceContext";
 
+const editorLifecycleEventBehavior = {
+  "editor:mount": { cardinality: "once", replay: "last" },
+  "editor:initialize": { cardinality: "once", replay: "last" },
+  "editor:unmount": { cardinality: "once", replay: "last" },
+} as const;
+
 export const ExcalidrawContainerContext = React.createContext<{
   container: HTMLDivElement | null;
   id: string | null;
@@ -545,6 +552,15 @@ const ExcalidrawActionManagerContext = React.createContext<ActionManager>(
 );
 ExcalidrawActionManagerContext.displayName = "ExcalidrawActionManagerContext";
 
+export const ExcalidrawAPIContext =
+  React.createContext<ExcalidrawImperativeAPI | null>(null);
+ExcalidrawAPIContext.displayName = "ExcalidrawAPIContext";
+
+export const ExcalidrawAPISetContext = React.createContext<
+  ((api: ExcalidrawImperativeAPI | null) => void) | null
+>(null);
+ExcalidrawAPISetContext.displayName = "ExcalidrawAPISetContext";
+
 export const useApp = () => useContext(AppContext);
 export const useAppProps = () => useContext(AppPropsContext);
 export const useEditorInterface = () =>
@@ -561,6 +577,10 @@ export const useExcalidrawSetAppState = () =>
   useContext(ExcalidrawSetAppStateContext);
 export const useExcalidrawActionManager = () =>
   useContext(ExcalidrawActionManagerContext);
+/**
+ * Requires wrapping your component in <ExcalidrawAPIContext.Provider>
+ */
+export const useExcalidrawAPI = () => useContext(ExcalidrawAPIContext);
 
 let didTapTwice: boolean = false;
 let tappedTwiceTimer = 0;
@@ -595,6 +615,7 @@ const gesture: Gesture = {
 class App extends React.Component<AppProps, AppState> {
   canvas: AppClassProperties["canvas"];
   interactiveCanvas: AppClassProperties["interactiveCanvas"] = null;
+  public sessionExportThemeOverride: AppState["theme"] | undefined;
   rc: RoughCanvas;
   unmounted: boolean = false;
   actionManager: ActionManager;
@@ -634,12 +655,26 @@ class App extends React.Component<AppProps, AppState> {
    * insert to DOM before user initially scrolls to them) */
   private initializedEmbeds = new Set<ExcalidrawIframeLikeElement["id"]>();
 
-  private handleToastClose = () => {
-    this.setToast(null);
-  };
-
   private elementsPendingErasure: ElementsPendingErasure = new Set();
 
+  private _initialized = false;
+
+  private readonly editorLifecycleEvents = new AppEventBus<
+    ExcalidrawImperativeAPIEventMap,
+    typeof editorLifecycleEventBehavior
+  >(editorLifecycleEventBehavior);
+
+  public onEvent = this.editorLifecycleEvents.on.bind(
+    this.editorLifecycleEvents,
+  ) as AppEventBus<
+    ExcalidrawImperativeAPIEventMap,
+    typeof editorLifecycleEventBehavior
+  >["on"];
+
+  private appStateObserver = new AppStateObserver(() => this.state);
+
+  public onStateChange: OnStateChange = this.appStateObserver.onStateChange;
+
   public flowChartCreator: FlowChartCreator = new FlowChartCreator();
   private flowChartNavigator: FlowChartNavigator = new FlowChartNavigator();
 
@@ -695,11 +730,56 @@ class App extends React.Component<AppProps, AppState> {
   >();
   onRemoveEventListenersEmitter = new Emitter<[]>();
 
+  api: ExcalidrawImperativeAPI;
+
+  private createExcalidrawAPI(): ExcalidrawImperativeAPI {
+    const api: ExcalidrawImperativeAPI = {
+      isDestroyed: false,
+      updateScene: this.updateScene,
+      applyDeltas: this.applyDeltas,
+      mutateElement: this.mutateElement,
+      updateLibrary: this.library.updateLibrary,
+      addFiles: this.addFiles,
+      resetScene: this.resetScene,
+      getSceneElementsIncludingDeleted: this.getSceneElementsIncludingDeleted,
+      getSceneElementsMapIncludingDeleted:
+        this.getSceneElementsMapIncludingDeleted,
+      history: {
+        clear: this.resetHistory,
+      },
+      scrollToContent: this.scrollToContent,
+      getSceneElements: this.getSceneElements,
+      getAppState: () => this.state,
+      getFiles: () => this.files,
+      getName: this.getName,
+      registerAction: (action: Action) => {
+        this.actionManager.registerAction(action);
+      },
+      refresh: this.refresh,
+      setToast: this.setToast,
+      id: this.id,
+      setActiveTool: this.setActiveTool,
+      setCursor: this.setCursor,
+      resetCursor: this.resetCursor,
+      getEditorInterface: () => this.editorInterface,
+      updateFrameRendering: this.updateFrameRendering,
+      toggleSidebar: this.toggleSidebar,
+      onChange: (cb) => this.onChangeEmitter.on(cb),
+      onIncrement: (cb) => this.store.onStoreIncrementEmitter.on(cb),
+      onPointerDown: (cb) => this.onPointerDownEmitter.on(cb),
+      onPointerUp: (cb) => this.onPointerUpEmitter.on(cb),
+      onScrollChange: (cb) => this.onScrollChangeEmitter.on(cb),
+      onUserFollow: (cb) => this.onUserFollowEmitter.on(cb),
+      onStateChange: this.onStateChange,
+      onEvent: this.onEvent,
+    };
+    return api;
+  }
+
   constructor(props: AppProps) {
     super(props);
     const defaultAppState = getDefaultAppState();
     const {
-      excalidrawAPI,
       viewModeEnabled = false,
       zenModeEnabled = false,
       gridModeEnabled = false,
@@ -707,9 +787,11 @@ class App extends React.Component<AppProps, AppState> {
       theme = defaultAppState.theme,
       name = `${t("labels.untitled")}-${getDateTime()}`,
     } = props;
+
     this.state = {
       ...defaultAppState,
       theme,
+      exportWithDarkMode: theme === THEME.DARK,
       isLoading: true,
       ...this.getCanvasOffsets(),
       viewModeEnabled,
@@ -742,51 +824,6 @@ class App extends React.Component<AppProps, AppState> {
     this.store = new Store(this);
     this.history = new History(this.store);
 
-    if (excalidrawAPI) {
-      const api: ExcalidrawImperativeAPI = {
-        updateScene: this.updateScene,
-        applyDeltas: this.applyDeltas,
-        mutateElement: this.mutateElement,
-        updateLibrary: this.library.updateLibrary,
-        addFiles: this.addFiles,
-        resetScene: this.resetScene,
-        getSceneElementsIncludingDeleted: this.getSceneElementsIncludingDeleted,
-        getSceneElementsMapIncludingDeleted:
-          this.getSceneElementsMapIncludingDeleted,
-        history: {
-          clear: this.resetHistory,
-        },
-        scrollToContent: this.scrollToContent,
-        getSceneElements: this.getSceneElements,
-        getAppState: () => this.state,
-        getFiles: () => this.files,
-        getName: this.getName,
-        registerAction: (action: Action) => {
-          this.actionManager.registerAction(action);
-        },
-        refresh: this.refresh,
-        setToast: this.setToast,
-        id: this.id,
-        setActiveTool: this.setActiveTool,
-        setCursor: this.setCursor,
-        resetCursor: this.resetCursor,
-        getEditorInterface: () => this.editorInterface,
-        updateFrameRendering: this.updateFrameRendering,
-        toggleSidebar: this.toggleSidebar,
-        onChange: (cb) => this.onChangeEmitter.on(cb),
-        onIncrement: (cb) => this.store.onStoreIncrementEmitter.on(cb),
-        onPointerDown: (cb) => this.onPointerDownEmitter.on(cb),
-        onPointerUp: (cb) => this.onPointerUpEmitter.on(cb),
-        onScrollChange: (cb) => this.onScrollChangeEmitter.on(cb),
-        onUserFollow: (cb) => this.onUserFollowEmitter.on(cb),
-      } as const;
-      if (typeof excalidrawAPI === "function") {
-        excalidrawAPI(api);
-      } else {
-        console.error("excalidrawAPI should be a function!");
-      }
-    }
-
     this.excalidrawContainerValue = {
       container: this.excalidrawContainerRef.current,
       id: this.id,
@@ -798,6 +835,12 @@ class App extends React.Component<AppProps, AppState> {
     this.actionManager.registerAll(actions);
     this.actionManager.registerAction(createUndoAction(this.history));
     this.actionManager.registerAction(createRedoAction(this.history));
+
+    // in case internal editor APIs call this early, otherwise we need
+    // to construct this in componentDidMount because componentWillUnmount
+    // will invalidate it (so in StrictMode, doing this in constructor alone
+    // would be a problem)
+    this.api = this.createExcalidrawAPI();
   }
 
   updateEditorAtom = <Value, Args extends unknown[], Result>(
@@ -2040,282 +2083,279 @@ class App extends React.Component<AppProps, AppState> {
         onPointerEnter={this.toggleOverscrollBehavior}
         onPointerLeave={this.toggleOverscrollBehavior}
       >
-        <AppContext.Provider value={this}>
-          <AppPropsContext.Provider value={this.props}>
-            <ExcalidrawContainerContext.Provider
-              value={this.excalidrawContainerValue}
-            >
-              <EditorInterfaceContext.Provider value={this.editorInterface}>
-                <ExcalidrawSetAppStateContext.Provider value={this.setAppState}>
-                  <ExcalidrawAppStateContext.Provider value={this.state}>
-                    <ExcalidrawElementsContext.Provider
-                      value={this.scene.getNonDeletedElements()}
-                    >
-                      <ExcalidrawActionManagerContext.Provider
-                        value={this.actionManager}
+        <ExcalidrawAPIContext.Provider value={this.api}>
+          <AppContext.Provider value={this}>
+            <AppPropsContext.Provider value={this.props}>
+              <ExcalidrawContainerContext.Provider
+                value={this.excalidrawContainerValue}
+              >
+                <EditorInterfaceContext.Provider value={this.editorInterface}>
+                  <ExcalidrawSetAppStateContext.Provider
+                    value={this.setAppState}
+                  >
+                    <ExcalidrawAppStateContext.Provider value={this.state}>
+                      <ExcalidrawElementsContext.Provider
+                        value={this.scene.getNonDeletedElements()}
                       >
-                        <LayerUI
-                          canvas={this.canvas}
-                          appState={this.state}
-                          files={this.files}
-                          setAppState={this.setAppState}
-                          actionManager={this.actionManager}
-                          elements={this.scene.getNonDeletedElements()}
-                          onLockToggle={this.toggleLock}
-                          onPenModeToggle={this.togglePenMode}
-                          onHandToolToggle={this.onHandToolToggle}
-                          langCode={getLanguage().code}
-                          renderTopLeftUI={renderTopLeftUI}
-                          renderTopRightUI={renderTopRightUI}
-                          renderCustomStats={renderCustomStats}
-                          showExitZenModeBtn={
-                            typeof this.props?.zenModeEnabled === "undefined" &&
-                            this.state.zenModeEnabled
-                          }
-                          UIOptions={this.props.UIOptions}
-                          onExportImage={this.onExportImage}
-                          renderWelcomeScreen={
-                            !this.state.isLoading &&
-                            this.state.showWelcomeScreen &&
-                            this.state.activeTool.type ===
-                              this.state.preferredSelectionTool.type &&
-                            !this.state.zenModeEnabled &&
-                            !this.scene.getElementsIncludingDeleted().length
-                          }
-                          app={this}
-                          isCollaborating={this.props.isCollaborating}
-                          generateLinkForSelection={
-                            this.props.generateLinkForSelection
-                          }
+                        <ExcalidrawActionManagerContext.Provider
+                          value={this.actionManager}
                         >
-                          {this.props.children}
-                        </LayerUI>
+                          <LayerUI
+                            canvas={this.canvas}
+                            appState={this.state}
+                            files={this.files}
+                            setAppState={this.setAppState}
+                            actionManager={this.actionManager}
+                            elements={this.scene.getNonDeletedElements()}
+                            onLockToggle={this.toggleLock}
+                            onPenModeToggle={this.togglePenMode}
+                            onHandToolToggle={this.onHandToolToggle}
+                            langCode={getLanguage().code}
+                            renderTopLeftUI={renderTopLeftUI}
+                            renderTopRightUI={renderTopRightUI}
+                            renderCustomStats={renderCustomStats}
+                            showExitZenModeBtn={
+                              typeof this.props?.zenModeEnabled ===
+                                "undefined" && this.state.zenModeEnabled
+                            }
+                            UIOptions={this.props.UIOptions}
+                            onExportImage={this.onExportImage}
+                            renderWelcomeScreen={
+                              !this.state.isLoading &&
+                              this.state.showWelcomeScreen &&
+                              this.state.activeTool.type ===
+                                this.state.preferredSelectionTool.type &&
+                              !this.state.zenModeEnabled &&
+                              !this.scene.getElementsIncludingDeleted().length
+                            }
+                            app={this}
+                            isCollaborating={this.props.isCollaborating}
+                            generateLinkForSelection={
+                              this.props.generateLinkForSelection
+                            }
+                          >
+                            {this.props.children}
+                          </LayerUI>
 
-                        <div className="excalidraw-textEditorContainer" />
-                        <div className="excalidraw-contextMenuContainer" />
-                        <div className="excalidraw-eye-dropper-container" />
-                        <SVGLayer
-                          trails={[
-                            this.laserTrails,
-                            this.lassoTrail,
-                            this.eraserTrail,
-                          ]}
-                        />
-                        {selectedElements.length === 1 &&
-                          this.state.openDialog?.name !==
-                            "elementLinkSelector" &&
-                          this.state.showHyperlinkPopup && (
-                            <Hyperlink
-                              key={firstSelectedElement.id}
-                              element={firstSelectedElement}
-                              scene={this.scene}
-                              setAppState={this.setAppState}
-                              onLinkOpen={this.props.onLinkOpen}
-                              setToast={this.setToast}
-                              updateEmbedValidationStatus={
-                                this.updateEmbedValidationStatus
-                              }
+                          <div className="excalidraw-textEditorContainer" />
+                          <div className="excalidraw-contextMenuContainer" />
+                          <div className="excalidraw-eye-dropper-container" />
+                          <SVGLayer
+                            trails={[
+                              this.laserTrails,
+                              this.lassoTrail,
+                              this.eraserTrail,
+                            ]}
+                          />
+                          {selectedElements.length === 1 &&
+                            this.state.openDialog?.name !==
+                              "elementLinkSelector" &&
+                            this.state.showHyperlinkPopup && (
+                              <Hyperlink
+                                key={firstSelectedElement.id}
+                                element={firstSelectedElement}
+                                scene={this.scene}
+                                setAppState={this.setAppState}
+                                onLinkOpen={this.props.onLinkOpen}
+                                setToast={this.setToast}
+                                updateEmbedValidationStatus={
+                                  this.updateEmbedValidationStatus
+                                }
+                              />
+                            )}
+                          {this.props.aiEnabled !== false &&
+                            selectedElements.length === 1 &&
+                            isMagicFrameElement(firstSelectedElement) && (
+                              <ElementCanvasButtons
+                                element={firstSelectedElement}
+                                elementsMap={elementsMap}
+                              >
+                                <ElementCanvasButton
+                                  title={t("labels.convertToCode")}
+                                  icon={MagicIcon}
+                                  checked={false}
+                                  onChange={() =>
+                                    this.onMagicFrameGenerate(
+                                      firstSelectedElement,
+                                      "button",
+                                    )
+                                  }
+                                />
+                              </ElementCanvasButtons>
+                            )}
+                          {selectedElements.length === 1 &&
+                            isIframeElement(firstSelectedElement) &&
+                            firstSelectedElement.customData?.generationData
+                              ?.status === "done" && (
+                              <ElementCanvasButtons
+                                element={firstSelectedElement}
+                                elementsMap={elementsMap}
+                              >
+                                <ElementCanvasButton
+                                  title={t("labels.copySource")}
+                                  icon={copyIcon}
+                                  checked={false}
+                                  onChange={() =>
+                                    this.onIframeSrcCopy(firstSelectedElement)
+                                  }
+                                />
+                                <ElementCanvasButton
+                                  title="Enter fullscreen"
+                                  icon={fullscreenIcon}
+                                  checked={false}
+                                  onChange={() => {
+                                    const iframe =
+                                      this.getHTMLIFrameElement(
+                                        firstSelectedElement,
+                                      );
+                                    if (iframe) {
+                                      try {
+                                        iframe.requestFullscreen();
+                                        this.setState({
+                                          activeEmbeddable: {
+                                            element: firstSelectedElement,
+                                            state: "active",
+                                          },
+                                          selectedElementIds: {
+                                            [firstSelectedElement.id]: true,
+                                          },
+                                          newElement: null,
+                                          selectionElement: null,
+                                        });
+                                      } catch (err: any) {
+                                        console.warn(err);
+                                        this.setState({
+                                          errorMessage:
+                                            "Couldn't enter fullscreen",
+                                        });
+                                      }
+                                    }
+                                  }}
+                                />
+                              </ElementCanvasButtons>
+                            )}
+
+                          {this.state.contextMenu && (
+                            <ContextMenu
+                              items={this.state.contextMenu.items}
+                              top={this.state.contextMenu.top}
+                              left={this.state.contextMenu.left}
+                              actionManager={this.actionManager}
+                              onClose={(callback) => {
+                                this.setState({ contextMenu: null }, () => {
+                                  this.focusContainer();
+                                  callback?.();
+                                });
+                              }}
                             />
                           )}
-                        {this.props.aiEnabled !== false &&
-                          selectedElements.length === 1 &&
-                          isMagicFrameElement(firstSelectedElement) && (
-                            <ElementCanvasButtons
-                              element={firstSelectedElement}
-                              elementsMap={elementsMap}
-                            >
-                              <ElementCanvasButton
-                                title={t("labels.convertToCode")}
-                                icon={MagicIcon}
-                                checked={false}
-                                onChange={() =>
-                                  this.onMagicFrameGenerate(
-                                    firstSelectedElement,
-                                    "button",
-                                  )
-                                }
-                              />
-                            </ElementCanvasButtons>
-                          )}
-                        {selectedElements.length === 1 &&
-                          isIframeElement(firstSelectedElement) &&
-                          firstSelectedElement.customData?.generationData
-                            ?.status === "done" && (
-                            <ElementCanvasButtons
-                              element={firstSelectedElement}
-                              elementsMap={elementsMap}
-                            >
-                              <ElementCanvasButton
-                                title={t("labels.copySource")}
-                                icon={copyIcon}
-                                checked={false}
-                                onChange={() =>
-                                  this.onIframeSrcCopy(firstSelectedElement)
-                                }
-                              />
-                              <ElementCanvasButton
-                                title="Enter fullscreen"
-                                icon={fullscreenIcon}
-                                checked={false}
-                                onChange={() => {
-                                  const iframe =
-                                    this.getHTMLIFrameElement(
-                                      firstSelectedElement,
-                                    );
-                                  if (iframe) {
-                                    try {
-                                      iframe.requestFullscreen();
-                                      this.setState({
-                                        activeEmbeddable: {
-                                          element: firstSelectedElement,
-                                          state: "active",
-                                        },
-                                        selectedElementIds: {
-                                          [firstSelectedElement.id]: true,
-                                        },
-                                        newElement: null,
-                                        selectionElement: null,
-                                      });
-                                    } catch (err: any) {
-                                      console.warn(err);
-                                      this.setState({
-                                        errorMessage:
-                                          "Couldn't enter fullscreen",
-                                      });
-                                    }
-                                  }
-                                }}
-                              />
-                            </ElementCanvasButtons>
-                          )}
-
-                        {this.state.toast !== null && (
-                          <Toast
-                            message={this.state.toast.message}
-                            onClose={this.handleToastClose}
-                            duration={this.state.toast.duration}
-                            closable={this.state.toast.closable}
-                          />
-                        )}
-
-                        {this.state.contextMenu && (
-                          <ContextMenu
-                            items={this.state.contextMenu.items}
-                            top={this.state.contextMenu.top}
-                            left={this.state.contextMenu.left}
-                            actionManager={this.actionManager}
-                            onClose={(callback) => {
-                              this.setState({ contextMenu: null }, () => {
-                                this.focusContainer();
-                                callback?.();
-                              });
-                            }}
-                          />
-                        )}
-                        <StaticCanvas
-                          canvas={this.canvas}
-                          rc={this.rc}
-                          elementsMap={elementsMap}
-                          allElementsMap={allElementsMap}
-                          visibleElements={visibleElements}
-                          sceneNonce={sceneNonce}
-                          selectionNonce={
-                            this.state.selectionElement?.versionNonce
-                          }
-                          scale={window.devicePixelRatio}
-                          appState={this.state}
-                          renderConfig={{
-                            imageCache: this.imageCache,
-                            isExporting: false,
-                            renderGrid: isGridModeEnabled(this),
-                            canvasBackgroundColor:
-                              this.state.viewBackgroundColor,
-                            embedsValidationStatus: this.embedsValidationStatus,
-                            elementsPendingErasure: this.elementsPendingErasure,
-                            pendingFlowchartNodes:
-                              this.flowChartCreator.pendingNodes,
-                            theme: this.state.theme,
-                          }}
-                        />
-                        {this.state.newElement && (
-                          <NewElementCanvas
-                            appState={this.state}
-                            scale={window.devicePixelRatio}
+                          <StaticCanvas
+                            canvas={this.canvas}
                             rc={this.rc}
                             elementsMap={elementsMap}
                             allElementsMap={allElementsMap}
+                            visibleElements={visibleElements}
+                            sceneNonce={sceneNonce}
+                            selectionNonce={
+                              this.state.selectionElement?.versionNonce
+                            }
+                            scale={window.devicePixelRatio}
+                            appState={this.state}
                             renderConfig={{
                               imageCache: this.imageCache,
                               isExporting: false,
-                              renderGrid: false,
+                              renderGrid: isGridModeEnabled(this),
                               canvasBackgroundColor:
                                 this.state.viewBackgroundColor,
                               embedsValidationStatus:
                                 this.embedsValidationStatus,
                               elementsPendingErasure:
                                 this.elementsPendingErasure,
-                              pendingFlowchartNodes: null,
+                              pendingFlowchartNodes:
+                                this.flowChartCreator.pendingNodes,
                               theme: this.state.theme,
                             }}
                           />
-                        )}
-                        <InteractiveCanvas
-                          app={this}
-                          containerRef={this.excalidrawContainerRef}
-                          canvas={this.interactiveCanvas}
-                          elementsMap={elementsMap}
-                          visibleElements={visibleElements}
-                          allElementsMap={allElementsMap}
-                          selectedElements={selectedElements}
-                          sceneNonce={sceneNonce}
-                          selectionNonce={
-                            this.state.selectionElement?.versionNonce
-                          }
-                          scale={window.devicePixelRatio}
-                          appState={this.state}
-                          renderScrollbars={
-                            this.props.renderScrollbars === true
-                          }
-                          editorInterface={this.editorInterface}
-                          renderInteractiveSceneCallback={
-                            this.renderInteractiveSceneCallback
-                          }
-                          handleCanvasRef={this.handleInteractiveCanvasRef}
-                          onContextMenu={this.handleCanvasContextMenu}
-                          onPointerMove={this.handleCanvasPointerMove}
-                          onPointerUp={this.handleCanvasPointerUp}
-                          onPointerCancel={this.removePointer}
-                          onTouchMove={this.handleTouchMove}
-                          onPointerDown={this.handleCanvasPointerDown}
-                          onDoubleClick={this.handleCanvasDoubleClick}
-                        />
-                        {this.state.userToFollow && (
-                          <FollowMode
-                            width={this.state.width}
-                            height={this.state.height}
-                            userToFollow={this.state.userToFollow}
-                            onDisconnect={this.maybeUnfollowRemoteUser}
-                          />
-                        )}
-                        {this.renderFrameNames()}
-                        {this.state.activeLockedId && (
-                          <UnlockPopup
+                          {this.state.newElement && (
+                            <NewElementCanvas
+                              appState={this.state}
+                              scale={window.devicePixelRatio}
+                              rc={this.rc}
+                              elementsMap={elementsMap}
+                              allElementsMap={allElementsMap}
+                              renderConfig={{
+                                imageCache: this.imageCache,
+                                isExporting: false,
+                                renderGrid: false,
+                                canvasBackgroundColor:
+                                  this.state.viewBackgroundColor,
+                                embedsValidationStatus:
+                                  this.embedsValidationStatus,
+                                elementsPendingErasure:
+                                  this.elementsPendingErasure,
+                                pendingFlowchartNodes: null,
+                                theme: this.state.theme,
+                              }}
+                            />
+                          )}
+                          <InteractiveCanvas
                             app={this}
-                            activeLockedId={this.state.activeLockedId}
+                            containerRef={this.excalidrawContainerRef}
+                            canvas={this.interactiveCanvas}
+                            elementsMap={elementsMap}
+                            visibleElements={visibleElements}
+                            allElementsMap={allElementsMap}
+                            selectedElements={selectedElements}
+                            sceneNonce={sceneNonce}
+                            selectionNonce={
+                              this.state.selectionElement?.versionNonce
+                            }
+                            scale={window.devicePixelRatio}
+                            appState={this.state}
+                            renderScrollbars={
+                              this.props.renderScrollbars === true
+                            }
+                            editorInterface={this.editorInterface}
+                            renderInteractiveSceneCallback={
+                              this.renderInteractiveSceneCallback
+                            }
+                            handleCanvasRef={this.handleInteractiveCanvasRef}
+                            onContextMenu={this.handleCanvasContextMenu}
+                            onPointerMove={this.handleCanvasPointerMove}
+                            onPointerUp={this.handleCanvasPointerUp}
+                            onPointerCancel={this.removePointer}
+                            onTouchMove={this.handleTouchMove}
+                            onPointerDown={this.handleCanvasPointerDown}
+                            onDoubleClick={this.handleCanvasDoubleClick}
                           />
-                        )}
-                        {showShapeSwitchPanel && (
-                          <ConvertElementTypePopup app={this} />
-                        )}
-                      </ExcalidrawActionManagerContext.Provider>
-                      {this.renderEmbeddables()}
-                    </ExcalidrawElementsContext.Provider>
-                  </ExcalidrawAppStateContext.Provider>
-                </ExcalidrawSetAppStateContext.Provider>
-              </EditorInterfaceContext.Provider>
-            </ExcalidrawContainerContext.Provider>
-          </AppPropsContext.Provider>
-        </AppContext.Provider>
+                          {this.state.userToFollow && (
+                            <FollowMode
+                              width={this.state.width}
+                              height={this.state.height}
+                              userToFollow={this.state.userToFollow}
+                              onDisconnect={this.maybeUnfollowRemoteUser}
+                            />
+                          )}
+                          {this.renderFrameNames()}
+                          {this.state.activeLockedId && (
+                            <UnlockPopup
+                              app={this}
+                              activeLockedId={this.state.activeLockedId}
+                            />
+                          )}
+                          {showShapeSwitchPanel && (
+                            <ConvertElementTypePopup app={this} />
+                          )}
+                        </ExcalidrawActionManagerContext.Provider>
+                        {this.renderEmbeddables()}
+                      </ExcalidrawElementsContext.Provider>
+                    </ExcalidrawAppStateContext.Provider>
+                  </ExcalidrawSetAppStateContext.Provider>
+                </EditorInterfaceContext.Provider>
+              </ExcalidrawContainerContext.Provider>
+            </AppPropsContext.Provider>
+          </AppContext.Provider>
+        </ExcalidrawAPIContext.Provider>
       </div>
     );
   }
@@ -2972,6 +3012,8 @@ class App extends React.Component<AppProps, AppState> {
 
   public async componentDidMount() {
     this.unmounted = false;
+    this.api = this.createExcalidrawAPI();
+
     this.excalidrawContainerValue.container =
       this.excalidrawContainerRef.current;
 
@@ -3013,12 +3055,10 @@ class App extends React.Component<AppProps, AppState> {
       this.history.record(increment.delta);
     });
 
-    const { onIncrement } = this.props;
-
     // per. optimmisation, only subscribe if there is the `onIncrement` prop registered, to avoid unnecessary computation
-    if (onIncrement) {
+    if (this.props.onIncrement) {
       this.store.onStoreIncrementEmitter.on((increment) => {
-        onIncrement(increment);
+        this.props.onIncrement?.(increment);
       });
     }
 
@@ -3052,10 +3092,43 @@ class App extends React.Component<AppProps, AppState> {
         errorMessage: <BraveMeasureTextError />,
       });
     }
+
+    const mountPayload = {
+      excalidrawAPI: this.api,
+      container: this.excalidrawContainerRef.current,
+    };
+
+    this.editorLifecycleEvents.emit("editor:mount", mountPayload);
+    this.props.onMount?.(mountPayload);
+    this.props.onExcalidrawAPI?.(this.api);
   }
 
   public componentWillUnmount() {
+    // we're recreating the api object reference so that the
+    // <ExcalidrawAPIContext.Provider/> picks up on it
+    this.api = { ...this.api, isDestroyed: true };
+
+    for (const key of Object.keys(this.api) as (keyof typeof this.api)[]) {
+      if (
+        (key.startsWith("get") ||
+          key === "onStateChange" ||
+          key === "onEvent") &&
+        typeof this.api[key] === "function"
+      ) {
+        (this.api as any)[key] = () => {
+          throw new Error(
+            "ExcalidrawAPI is no longer usable after the editor has been unmounted and will return invalid/empty data. You should check for `ExcalidrawAPI.isDestroyed` before calling get* methods on subscribing to state/event changes.",
+          );
+        };
+      }
+    }
+
+    this.editorLifecycleEvents.emit("editor:unmount");
+    this.props.onUnmount?.();
+    this.props.onExcalidrawAPI?.(null);
+
     (window as any).launchQueue?.setConsumer(() => {});
+
     this.renderer.destroy();
     this.scene.destroy();
     this.scene = new Scene();
@@ -3072,6 +3145,8 @@ class App extends React.Component<AppProps, AppState> {
     this.onChangeEmitter.clear();
     this.store.onStoreIncrementEmitter.clear();
     this.store.onDurableIncrementEmitter.clear();
+    this.appStateObserver.clear();
+    this.editorLifecycleEvents.clear();
     ShapeCache.destroy();
     SnapCache.destroy();
     clearTimeout(touchTimeout);
@@ -3237,10 +3312,26 @@ class App extends React.Component<AppProps, AppState> {
   }
 
   componentDidUpdate(prevProps: AppProps, prevState: AppState) {
+    // must be updated *before* state change listeners are triggered below
+    if (!this._initialized && !this.state.isLoading) {
+      this._initialized = true;
+      this.editorLifecycleEvents.emit("editor:initialize", this.api);
+      this.props.onInitialize?.(this.api);
+    }
+
+    this.appStateObserver.flush(prevState);
+
     this.updateEmbeddables();
     const elements = this.scene.getElementsIncludingDeleted();
     const elementsMap = this.scene.getElementsMapIncludingDeleted();
 
+    const shouldExportWithDarkMode =
+      (this.sessionExportThemeOverride ?? this.state.theme) === THEME.DARK;
+
+    if (this.state.exportWithDarkMode !== shouldExportWithDarkMode) {
+      this.setState({ exportWithDarkMode: shouldExportWithDarkMode });
+    }
+
     if (!this.state.showWelcomeScreen && !elements.length) {
       this.setState({ showWelcomeScreen: true });
     }
@@ -3612,7 +3703,7 @@ class App extends React.Component<AppProps, AppState> {
     if (!isPlainPaste && isMaybeMermaidDefinition(data.text)) {
       const api = await import("@excalidraw/mermaid-to-excalidraw");
       try {
-        const { elements: skeletonElements, files } =
+        const { elements: skeletonElements, files = {} } =
           await api.parseMermaidToExcalidraw(data.text);
 
         const elements = convertToExcalidrawElements(skeletonElements, {
@@ -4315,13 +4406,7 @@ class App extends React.Component<AppProps, AppState> {
     this.setState(state);
   };
 
-  setToast = (
-    toast: {
-      message: string;
-      closable?: boolean;
-      duration?: number;
-    } | null,
-  ) => {
+  setToast = (toast: AppState["toast"]) => {
     this.setState({ toast });
   };
 
@@ -5146,7 +5231,8 @@ class App extends React.Component<AppProps, AppState> {
       // eye dropper
       // -----------------------------------------------------------------------
       const lowerCased = event.key.toLocaleLowerCase();
-      const isPickingStroke = lowerCased === KEYS.S && event.shiftKey;
+      const isPickingStroke =
+        lowerCased === KEYS.S && event.shiftKey && !event[KEYS.CTRL_OR_CMD];
       const isPickingBackground =
         event.key === KEYS.I || (lowerCased === KEYS.G && event.shiftKey);
 
@@ -11593,7 +11679,7 @@ class App extends React.Component<AppProps, AppState> {
 
   loadFileToCanvas = async (
     file: File,
-    fileHandle: FileSystemHandle | null,
+    fileHandle: FileSystemFileHandle | null,
   ) => {
     file = await normalizeFile(file);
     try {

packages/excalidraw/components/AppStateObserver.ts

@@ -0,0 +1,208 @@
+import type { AppState, UnsubscribeCallback } from "../types";
+
+type StateChangeSelector =
+  | keyof AppState
+  | (keyof AppState)[]
+  | ((appState: AppState) => unknown);
+
+type StateChangePredicateOptions = {
+  predicate: (appState: AppState) => boolean;
+  callback?: (appState: AppState) => void;
+  once?: boolean;
+};
+
+type StateChangeArg = StateChangeSelector | StateChangePredicateOptions;
+
+type StateChangeListener = {
+  predicate: (appState: AppState, prevState: AppState) => boolean;
+  getValue: (appState: AppState) => unknown;
+  callback: (value: any, appState: AppState) => void;
+  once: boolean;
+};
+
+type NormalizedStateChange = {
+  predicate: StateChangeListener["predicate"];
+  getValue: StateChangeListener["getValue"];
+  callback?: StateChangeListener["callback"];
+  once: boolean;
+  matchesImmediately: boolean;
+};
+
+export type OnStateChange = {
+  <K extends keyof AppState>(
+    prop: K,
+    callback: (value: AppState[K], appState: AppState) => void,
+    opts?: { once: boolean },
+  ): UnsubscribeCallback;
+  <K extends keyof AppState>(prop: K): Promise<AppState[K]>;
+  (
+    prop: (keyof AppState)[],
+    callback: (appState: AppState, appState2: AppState) => void,
+    opts?: { once: boolean },
+  ): UnsubscribeCallback;
+  (prop: (keyof AppState)[]): Promise<AppState>;
+  <T>(
+    prop: (appState: AppState) => T,
+    callback: (value: T, appState: AppState) => void,
+    opts?: { once: boolean },
+  ): UnsubscribeCallback;
+  <T>(prop: (appState: AppState) => T): Promise<T>;
+  (opts: {
+    predicate: (appState: AppState) => boolean;
+    callback: (appState: AppState) => void;
+    once?: boolean;
+  }): UnsubscribeCallback;
+  (opts: { predicate: (appState: AppState) => boolean }): Promise<AppState>;
+  (
+    selector: StateChangeSelector,
+    callback: (value: any, appState: AppState) => void,
+  ): any;
+};
+
+export class AppStateObserver {
+  private listeners: StateChangeListener[] = [];
+
+  constructor(private readonly getState: () => AppState) {}
+
+  private isStateChangePredicateOptions(
+    propOrOpts: StateChangeArg,
+  ): propOrOpts is StateChangePredicateOptions {
+    return (
+      typeof propOrOpts === "object" &&
+      !Array.isArray(propOrOpts) &&
+      "predicate" in propOrOpts
+    );
+  }
+
+  private subscribe(listener: StateChangeListener): UnsubscribeCallback {
+    this.listeners.push(listener);
+    return () => {
+      this.listeners = this.listeners.filter(
+        (existingListener) => existingListener !== listener,
+      );
+    };
+  }
+
+  private normalize(
+    propOrOpts: StateChangeArg,
+    callback?: (value: any, appState: AppState) => void,
+    opts?: { once: boolean },
+  ): NormalizedStateChange {
+    let predicate: StateChangeListener["predicate"];
+    let getValue: StateChangeListener["getValue"];
+    let normalizedCallback = callback;
+    let once = opts?.once ?? false;
+    let matchesImmediately = false;
+
+    if (this.isStateChangePredicateOptions(propOrOpts)) {
+      const {
+        predicate: predicateFn,
+        callback: callbackFromOpts,
+        once: onceFromOpts,
+      } = propOrOpts;
+
+      predicate = predicateFn;
+      getValue = (appState: AppState) => appState;
+      normalizedCallback = callbackFromOpts
+        ? (_value: AppState, appState: AppState) => callbackFromOpts(appState)
+        : undefined;
+      once = onceFromOpts ?? false;
+      matchesImmediately = predicateFn(this.getState());
+    } else if (typeof propOrOpts === "function") {
+      const selector = propOrOpts;
+      predicate = (appState: AppState, prevState: AppState) =>
+        selector(appState) !== selector(prevState);
+      getValue = (appState: AppState) => selector(appState);
+    } else if (Array.isArray(propOrOpts)) {
+      const keys = propOrOpts;
+      predicate = (appState: AppState, prevState: AppState) =>
+        keys.some((key) => appState[key] !== prevState[key]);
+      getValue = (appState: AppState) => appState;
+    } else {
+      const key = propOrOpts;
+      predicate = (appState: AppState, prevState: AppState) =>
+        appState[key] !== prevState[key];
+      getValue = (appState: AppState) => appState[key];
+    }
+
+    return {
+      predicate,
+      getValue,
+      callback: normalizedCallback,
+      once,
+      matchesImmediately,
+    };
+  }
+
+  public onStateChange: OnStateChange = ((
+    propOrOpts: StateChangeArg,
+    callback?: any,
+    opts?: { once: boolean },
+  ) => {
+    const {
+      predicate,
+      getValue,
+      callback: stateChangeCallback,
+      once,
+      matchesImmediately,
+    } = this.normalize(propOrOpts, callback, opts);
+
+    if (stateChangeCallback) {
+      if (matchesImmediately) {
+        queueMicrotask(() => {
+          const state = this.getState();
+          stateChangeCallback(getValue(state), state);
+        });
+        if (once) {
+          return () => {};
+        }
+      }
+
+      return this.subscribe({
+        predicate,
+        getValue,
+        callback: stateChangeCallback,
+        once,
+      });
+    }
+
+    if (matchesImmediately) {
+      return Promise.resolve(getValue(this.getState()));
+    }
+
+    return new Promise<any>((resolve) => {
+      this.subscribe({
+        predicate,
+        getValue,
+        callback: (value) => resolve(value),
+        once: true,
+      });
+    });
+  }) as OnStateChange;
+
+  public flush(prevState: AppState) {
+    if (!this.listeners.length) {
+      return;
+    }
+
+    const state = this.getState();
+    const listenersToKeep: StateChangeListener[] = [];
+
+    for (const listener of this.listeners) {
+      if (listener.predicate(state, prevState)) {
+        listener.callback(listener.getValue(state), state);
+        if (!listener.once) {
+          listenersToKeep.push(listener);
+        }
+      } else {
+        listenersToKeep.push(listener);
+      }
+    }
+
+    this.listeners = listenersToKeep;
+  }
+
+  public clear() {
+    this.listeners = [];
+  }
+}

packages/excalidraw/components/CommandPalette/CommandPalette.tsx

@@ -10,12 +10,11 @@ import {
   isWritableElement,
 } from "@excalidraw/common";
 
-import { actionToggleShapeSwitch } from "@excalidraw/excalidraw/actions/actionToggleShapeSwitch";
-
-import { getShortcutKey } from "@excalidraw/excalidraw/shortcut";
-
 import type { MarkRequired } from "@excalidraw/common/utility-types";
 
+import { actionToggleShapeSwitch } from "../../actions/actionToggleShapeSwitch";
+import { getShortcutKey } from "../../shortcut";
+
 import {
   actionClearCanvas,
   actionLink,

packages/excalidraw/components/ConvertElementTypePopup.tsx

@@ -1,7 +1,9 @@
 import { type ReactNode, useEffect, useMemo, useRef, useState } from "react";
 
 import {
+  bumpVersion,
   getLinearElementSubType,
+  mutateElement,
   updateElbowArrowPoints,
 } from "@excalidraw/element";
 
@@ -37,6 +39,8 @@ import {
   isProdEnv,
   mapFind,
   reduceToCommonValue,
+  ROUNDNESS,
+  sceneCoordsToViewportCoords,
   updateActiveTool,
 } from "@excalidraw/common";
 
@@ -71,12 +75,6 @@ import type {
 
 import type { Scene } from "@excalidraw/element";
 
-import {
-  bumpVersion,
-  mutateElement,
-  ROUNDNESS,
-  sceneCoordsToViewportCoords,
-} from "..";
 import { trackEvent } from "../analytics";
 import { atom } from "../editor-jotai";
 

packages/excalidraw/components/IconPicker.scss

@@ -6,14 +6,20 @@
     padding: 0.5rem;
     background: var(--popup-bg-color);
     border: 0 solid color.adjust(#fff, $alpha: -0.75);
-    box-shadow: var(--shadow-island);
+    box-shadow: var(--shadow-island-stronger);
     border-radius: 4px;
-    position: absolute;
     :root[dir="rtl"] & {
       padding: 0.4rem;
     }
   }
 
+  .picker-sections,
+  .picker-section {
+    display: flex;
+    flex-direction: column;
+    gap: 0.5rem;
+  }
+
   .picker-container button,
   .picker button {
     position: relative;
@@ -62,7 +68,13 @@
 
   .picker-collapsible {
     font-size: 0.75rem;
-    padding: 0.5rem 0;
+    padding: 0;
+    color: var(--text-primary-color);
+  }
+
+  .picker-section-label {
+    font-size: 0.75rem;
+    color: var(--text-primary-color);
   }
 
   .picker-keybinding {

packages/excalidraw/components/IconPicker.tsx

@@ -1,6 +1,6 @@
 import { Popover } from "radix-ui";
 import clsx from "clsx";
-import React, { useEffect } from "react";
+import React, { useEffect, useMemo } from "react";
 
 import { isArrowKey, KEYS } from "@excalidraw/common";
 
@@ -8,13 +8,15 @@ import { atom, useAtom } from "../editor-jotai";
 import { getLanguage, t } from "../i18n";
 
 import Collapsible from "./Stats/Collapsible";
-import { useEditorInterface, useExcalidrawContainer } from "./App";
+import { useExcalidrawContainer } from "./App";
 
 import "./IconPicker.scss";
 
 import type { JSX } from "react";
 
 const moreOptionsAtom = atom(false);
+const PICKER_COLUMNS = 4;
+const DEFAULT_SECTION_NAME = "default";
 
 type Option<T> = {
   value: T;
@@ -23,28 +25,73 @@ type Option<T> = {
   keyBinding: string | null;
 };
 
+type PickerSection<T> = {
+  name: string;
+  options: readonly Option<T>[];
+};
+
+const flattenOptions = <T,>(sections: readonly PickerSection<T>[]) =>
+  sections.flatMap((section) => section.options);
+
+const findOption = <T,>(
+  sections: readonly PickerSection<T>[],
+  predicate: (option: Option<T>) => boolean,
+) => {
+  for (const section of sections) {
+    const option = section.options.find(predicate);
+    if (option) {
+      return option;
+    }
+  }
+
+  return null;
+};
+
+const hasOption = <T,>(
+  sections: readonly PickerSection<T>[],
+  predicate: (option: Option<T>) => boolean,
+) => sections.some((section) => section.options.some(predicate));
+
+const getNavigationRows = <T,>(sections: readonly PickerSection<T>[]) =>
+  sections.flatMap((section) =>
+    Array.from(
+      { length: Math.ceil(section.options.length / PICKER_COLUMNS) },
+      (_, index) =>
+        section.options.slice(
+          index * PICKER_COLUMNS,
+          index * PICKER_COLUMNS + PICKER_COLUMNS,
+        ),
+    ),
+  );
+
 function Picker<T>({
-  options,
+  visibleSections,
+  hiddenSections = [],
   value,
   label,
   onChange,
   onClose,
-  numberOfOptionsToAlwaysShow = options.length,
 }: {
   label: string;
   value: T;
-  options: readonly Option<T>[];
+  visibleSections: readonly PickerSection<T>[];
+  hiddenSections?: readonly PickerSection<T>[];
   onChange: (value: T) => void;
   onClose: () => void;
-  numberOfOptionsToAlwaysShow?: number;
 }) {
-  const editorInterface = useEditorInterface();
   const { container } = useExcalidrawContainer();
+  const [showMoreOptions, setShowMoreOptions] = useAtom(moreOptionsAtom);
+  const allSections = [...visibleSections, ...hiddenSections];
+  const allOptions = flattenOptions(allSections);
+  const navigationRows = getNavigationRows([
+    ...visibleSections,
+    ...(showMoreOptions ? hiddenSections : []),
+  ]);
 
   const handleKeyDown = (event: React.KeyboardEvent) => {
-    const pressedOption = options.find(
+    const pressedOption = allOptions.find(
       (option) => option.keyBinding === event.key.toLowerCase(),
-    )!;
+    );
 
     if (!(event.metaKey || event.altKey || event.ctrlKey) && pressedOption) {
       // Keybinding navigation
@@ -52,17 +99,17 @@ function Picker<T>({
 
       event.preventDefault();
     } else if (event.key === KEYS.TAB) {
-      const index = options.findIndex((option) => option.value === value);
+      const index = allOptions.findIndex((option) => option.value === value);
       const nextIndex = event.shiftKey
-        ? (options.length + index - 1) % options.length
-        : (index + 1) % options.length;
-      onChange(options[nextIndex].value);
+        ? (allOptions.length + index - 1) % allOptions.length
+        : (index + 1) % allOptions.length;
+      onChange(allOptions[nextIndex].value);
     } else if (isArrowKey(event.key)) {
       // Arrow navigation
       const isRTL = getLanguage().rtl;
-      const index = options.findIndex((option) => option.value === value);
+      const index = allOptions.findIndex((option) => option.value === value);
       if (index !== -1) {
-        const length = options.length;
+        const length = allOptions.length;
         let nextIndex = index;
 
         switch (event.key) {
@@ -76,18 +123,60 @@ function Picker<T>({
             break;
           // Go the next row
           case KEYS.ARROW_DOWN: {
-            nextIndex = (index + (numberOfOptionsToAlwaysShow ?? 1)) % length;
+            const currentRowIndex = navigationRows.findIndex((row) =>
+              row.some((option) => option.value === value),
+            );
+            const currentRow = navigationRows[currentRowIndex];
+
+            if (currentRowIndex !== -1 && currentRow) {
+              const column = currentRow.findIndex(
+                (option) => option.value === value,
+              );
+              const nextRow =
+                navigationRows[(currentRowIndex + 1) % navigationRows.length];
+              const nextOption =
+                nextRow[Math.min(column, nextRow.length - 1)] ??
+                allOptions[index];
+
+              onChange(nextOption.value);
+              event.preventDefault();
+              event.nativeEvent.stopImmediatePropagation();
+              event.stopPropagation();
+              return;
+            }
             break;
           }
           // Go the previous row
           case KEYS.ARROW_UP: {
-            nextIndex =
-              (length + index - (numberOfOptionsToAlwaysShow ?? 1)) % length;
+            const currentRowIndex = navigationRows.findIndex((row) =>
+              row.some((option) => option.value === value),
+            );
+            const currentRow = navigationRows[currentRowIndex];
+
+            if (currentRowIndex !== -1 && currentRow) {
+              const column = currentRow.findIndex(
+                (option) => option.value === value,
+              );
+              const previousRow =
+                navigationRows[
+                  (navigationRows.length + currentRowIndex - 1) %
+                    navigationRows.length
+                ];
+              const previousOption =
+                previousRow[Math.min(column, previousRow.length - 1)] ??
+                allOptions[index];
+
+              onChange(previousOption.value);
+              event.preventDefault();
+              event.nativeEvent.stopImmediatePropagation();
+              event.stopPropagation();
+              return;
+            }
             break;
           }
         }
 
-        onChange(options[nextIndex].value);
+        onChange(allOptions[nextIndex].value);
       }
       event.preventDefault();
     } else if (event.key === KEYS.ESCAPE || event.key === KEYS.ENTER) {
@@ -99,38 +188,29 @@ function Picker<T>({
     event.stopPropagation();
   };
 
-  const [showMoreOptions, setShowMoreOptions] = useAtom(moreOptionsAtom);
-
-  const alwaysVisibleOptions = React.useMemo(
-    () => options.slice(0, numberOfOptionsToAlwaysShow),
-    [options, numberOfOptionsToAlwaysShow],
-  );
-  const moreOptions = React.useMemo(
-    () => options.slice(numberOfOptionsToAlwaysShow),
-    [options, numberOfOptionsToAlwaysShow],
-  );
-
   useEffect(() => {
-    if (!alwaysVisibleOptions.some((option) => option.value === value)) {
+    if (hasOption(hiddenSections, (option) => option.value === value)) {
       setShowMoreOptions(true);
     }
-  }, [value, alwaysVisibleOptions, setShowMoreOptions]);
+  }, [value, hiddenSections, setShowMoreOptions]);
 
-  const renderOptions = (options: Option<T>[]) => {
+  const renderOptions = (options: readonly Option<T>[]) => {
     return (
       <div className="picker-content">
-        {options.map((option, i) => (
+        {options.map((option) => (
           <button
             type="button"
             className={clsx("picker-option", {
               active: value === option.value,
             })}
-            onClick={(event) => {
+            onClick={() => {
               onChange(option.value);
             }}
-            title={`${option.text} ${
-              option.keyBinding && `— ${option.keyBinding.toUpperCase()}`
-            }`}
+            title={
+              option.keyBinding
+                ? `${option.text} — ${option.keyBinding.toUpperCase()}`
+                : option.text
+            }
             aria-label={option.text || "none"}
             aria-keyshortcuts={option.keyBinding || undefined}
             key={option.text}
@@ -153,26 +233,38 @@ function Picker<T>({
     );
   };
 
-  const isMobile = editorInterface.formFactor === "phone";
+  const renderSections = (sections: readonly PickerSection<T>[]) =>
+    sections.map((section, index) =>
+      section.name === DEFAULT_SECTION_NAME ? (
+        <React.Fragment key={`${section.name}-${index}`}>
+          {renderOptions(section.options)}
+        </React.Fragment>
+      ) : (
+        <div className="picker-section" key={`${section.name}-${index}`}>
+          <div className="picker-section-label">{section.name}</div>
+          {renderOptions(section.options)}
+        </div>
+      ),
+    );
 
   return (
     <Popover.Content
-      side={isMobile ? "right" : "bottom"}
+      className="picker"
+      role="dialog"
+      aria-modal="true"
+      aria-label={label}
+      side={"bottom"}
       align="start"
-      sideOffset={isMobile ? 8 : 12}
+      sideOffset={12}
+      alignOffset={12}
       style={{ zIndex: "var(--zIndex-ui-styles-popup)" }}
       onKeyDown={handleKeyDown}
       collisionBoundary={container ?? undefined}
     >
-      <div
-        className={`picker`}
-        role="dialog"
-        aria-modal="true"
-        aria-label={label}
-      >
-        {renderOptions(alwaysVisibleOptions)}
+      <div className="picker-sections">
+        {renderSections(visibleSections)}
 
-        {moreOptions.length > 0 && (
+        {hiddenSections.length > 0 && (
           <Collapsible
             label={t("labels.more_options")}
             open={showMoreOptions}
@@ -181,7 +273,9 @@ function Picker<T>({
             }}
             className="picker-collapsible"
           >
-            {renderOptions(moreOptions)}
+            <div className="picker-sections">
+              {renderSections(hiddenSections)}
+            </div>
           </Collapsible>
         )}
       </div>
@@ -192,49 +286,45 @@ function Picker<T>({
 export function IconPicker<T>({
   value,
   label,
-  options,
+  visibleSections,
+  hiddenSections,
   onChange,
-  group = "",
-  numberOfOptionsToAlwaysShow,
 }: {
   label: string;
   value: T;
-  options: readonly {
-    value: T;
-    text: string;
-    icon: JSX.Element;
-    keyBinding: string | null;
-  }[];
+  visibleSections: readonly PickerSection<T>[];
+  hiddenSections?: readonly PickerSection<T>[];
   onChange: (value: T) => void;
-  numberOfOptionsToAlwaysShow?: number;
-  group?: string;
 }) {
   const [isActive, setActive] = React.useState(false);
-  const rPickerButton = React.useRef<any>(null);
+  const selectedOption = useMemo(
+    () =>
+      findOption(visibleSections, (option) => option.value === value) ??
+      findOption(hiddenSections ?? [], (option) => option.value === value),
+    [visibleSections, hiddenSections, value],
+  );
 
   return (
     <div>
       <Popover.Root open={isActive} onOpenChange={(open) => setActive(open)}>
         <Popover.Trigger
-          name={group}
           type="button"
           aria-label={label}
           onClick={() => setActive(!isActive)}
-          ref={rPickerButton}
           className={isActive ? "active" : ""}
         >
-          {options.find((option) => option.value === value)?.icon}
+          {selectedOption?.icon}
         </Popover.Trigger>
         {isActive && (
           <Picker
-            options={options}
+            visibleSections={visibleSections}
+            hiddenSections={hiddenSections}
             value={value}
             label={label}
             onChange={onChange}
             onClose={() => {
               setActive(false);
             }}
-            numberOfOptionsToAlwaysShow={numberOfOptionsToAlwaysShow}
           />
         )}
       </Popover.Root>

packages/excalidraw/components/ImageExportDialog.tsx

@@ -59,6 +59,7 @@ type ImageExportModalProps = {
   actionManager: ActionManager;
   onExportImage: AppClassProperties["onExportImage"];
   name: string;
+  exportWithDarkMode: boolean;
 };
 
 const ImageExportModal = ({
@@ -68,6 +69,7 @@ const ImageExportModal = ({
   actionManager,
   onExportImage,
   name,
+  exportWithDarkMode,
 }: ImageExportModalProps) => {
   const hasSelection = isSomeElementSelected(
     elementsSnapshot,
@@ -79,15 +81,13 @@ const ImageExportModal = ({
   const [exportWithBackground, setExportWithBackground] = useState(
     appStateSnapshot.exportBackground,
   );
-  const [exportDarkMode, setExportDarkMode] = useState(
-    appStateSnapshot.exportWithDarkMode,
-  );
   const [embedScene, setEmbedScene] = useState(
     appStateSnapshot.exportEmbedScene,
   );
   const [exportScale, setExportScale] = useState(appStateSnapshot.exportScale);
 
   const previewRef = useRef<HTMLDivElement>(null);
+  const previewRenderRequestIdRef = useRef(0);
   const [renderError, setRenderError] = useState<Error | null>(null);
 
   const { onCopy, copyStatus, resetCopyStatus } = useCopyStatus();
@@ -99,7 +99,7 @@ const ImageExportModal = ({
   }, [
     projectName,
     exportWithBackground,
-    exportDarkMode,
+    exportWithDarkMode,
     exportScale,
     embedScene,
     resetCopyStatus,
@@ -122,13 +122,18 @@ const ImageExportModal = ({
       return;
     }
 
+    const requestId = ++previewRenderRequestIdRef.current;
+    const isStaleRequest = () => {
+      return requestId !== previewRenderRequestIdRef.current;
+    };
+
     exportToCanvas({
       elements: exportedElements,
       appState: {
         ...appStateSnapshot,
         name: projectName,
         exportBackground: exportWithBackground,
-        exportWithDarkMode: exportDarkMode,
+        exportWithDarkMode,
         exportScale,
         exportEmbedScene: embedScene,
       },
@@ -137,25 +142,41 @@ const ImageExportModal = ({
       maxWidthOrHeight: Math.max(maxWidth, maxHeight),
       exportingFrame,
     })
-      .then((canvas) => {
+      .then(async (canvas) => {
+        if (isStaleRequest()) {
+          return;
+        }
+
+        // If converting to blob fails, there's some problem that will likely
+        // prevent preview and export (e.g. canvas too big).
+        try {
+          await canvasToBlob(canvas);
+        } catch (error: any) {
+          if (error.name === "CANVAS_POSSIBLY_TOO_BIG") {
+            throw new Error(t("canvasError.canvasTooBig"));
+          }
+          throw error;
+        }
+
+        if (isStaleRequest()) {
+          return;
+        }
+
         setRenderError(null);
-        // if converting to blob fails, there's some problem that will
-        // likely prevent preview and export (e.g. canvas too big)
-        return canvasToBlob(canvas)
-          .then(() => {
-            previewNode.replaceChildren(canvas);
-          })
-          .catch((e) => {
-            if (e.name === "CANVAS_POSSIBLY_TOO_BIG") {
-              throw new Error(t("canvasError.canvasTooBig"));
-            }
-            throw e;
-          });
+        previewNode.replaceChildren(canvas);
       })
       .catch((error) => {
+        if (isStaleRequest()) {
+          return;
+        }
+
         console.error(error);
         setRenderError(error);
       });
+
+    return () => {
+      previewRenderRequestIdRef.current += 1;
+    };
   }, [
     appStateSnapshot,
     files,
@@ -163,7 +184,7 @@ const ImageExportModal = ({
     exportingFrame,
     projectName,
     exportWithBackground,
-    exportDarkMode,
+    exportWithDarkMode,
     exportScale,
     embedScene,
   ]);
@@ -233,9 +254,8 @@ const ImageExportModal = ({
         >
           <Switch
             name="exportDarkModeSwitch"
-            checked={exportDarkMode}
+            checked={exportWithDarkMode}
             onChange={(checked) => {
-              setExportDarkMode(checked);
               actionManager.executeAction(
                 actionExportWithDarkMode,
                 "ui",
@@ -399,6 +419,7 @@ export const ImageExportDialog = ({
         actionManager={actionManager}
         onExportImage={onExportImage}
         name={name}
+        exportWithDarkMode={appState.exportWithDarkMode}
       />
     </Dialog>
   );

packages/excalidraw/components/LayerUI.tsx

@@ -60,6 +60,7 @@ import { ImageExportDialog } from "./ImageExportDialog";
 import { Island } from "./Island";
 import { JSONExportDialog } from "./JSONExportDialog";
 import { LaserPointerButton } from "./LaserPointerButton";
+import { Toast } from "./Toast";
 
 import "./LayerUI.scss";
 import "./Toolbar.scss";
@@ -605,18 +606,30 @@ const LayerUI = ({
               showExitZenModeBtn={showExitZenModeBtn}
               renderWelcomeScreen={renderWelcomeScreen}
             />
-            {appState.scrolledOutside && (
-              <button
-                type="button"
-                className="scroll-back-to-content"
-                onClick={() => {
-                  setAppState((appState) => ({
-                    ...calculateScrollCenter(elements, appState),
-                  }));
-                }}
-              >
-                {t("buttons.scrollBackToContent")}
-              </button>
+            {(appState.toast || appState.scrolledOutside) && (
+              <div className="floating-status-stack">
+                {appState.toast && (
+                  <Toast
+                    message={appState.toast.message}
+                    onClose={() => setAppState({ toast: null })}
+                    duration={appState.toast.duration}
+                    closable={appState.toast.closable}
+                  />
+                )}
+                {!appState.toast && appState.scrolledOutside && (
+                  <button
+                    type="button"
+                    className="scroll-back-to-content"
+                    onClick={() => {
+                      setAppState((appState) => ({
+                        ...calculateScrollCenter(elements, appState),
+                      }));
+                    }}
+                  >
+                    {t("buttons.scrollBackToContent")}
+                  </button>
+                )}
+              </div>
             )}
           </div>
           {renderSidebars()}

packages/excalidraw/components/MobileToolBar.tsx

@@ -472,9 +472,9 @@ export const MobileToolBar = ({
                 onSelect={() => app.onMagicframeToolSelect()}
                 icon={MagicIcon}
                 data-testid="toolbar-magicframe"
+                badge={<DropdownMenu.Item.Badge>AI</DropdownMenu.Item.Badge>}
               >
                 {t("toolBar.magicframe")}
-                <DropdownMenu.Item.Badge>AI</DropdownMenu.Item.Badge>
               </DropdownMenu.Item>
             </>
           )}

packages/excalidraw/components/TTDDialog/Chat/TTDChatPanel.tsx

@@ -11,7 +11,7 @@ import { rateLimitsAtom } from "../TTDContext";
 
 import { ChatHistoryMenu } from "./ChatHistoryMenu";
 
-import { ChatInterface } from ".";
+import { ChatInterface } from "./ChatInterface";
 
 import type { TTDPanelAction } from "../TTDDialogPanel";
 

packages/excalidraw/components/TTDDialog/CodeMirrorEditor.tsx

@@ -0,0 +1,239 @@
+import { useEffect, useRef } from "react";
+import {
+  Decoration,
+  EditorView,
+  keymap,
+  lineNumbers,
+  placeholder as cmPlaceholder,
+  drawSelection,
+} from "@codemirror/view";
+import { Compartment, EditorState, type Extension } from "@codemirror/state";
+import {
+  defaultKeymap,
+  history,
+  historyKeymap,
+  redo,
+} from "@codemirror/commands";
+import { syntaxHighlighting, HighlightStyle } from "@codemirror/language";
+import { tags } from "@lezer/highlight";
+
+import type { Theme } from "@excalidraw/element/types";
+
+import { mermaidLite } from "./mermaid-lang-lite";
+
+export interface CodeMirrorEditorProps {
+  value: string;
+  onChange: (value: string) => void;
+  onKeyboardSubmit?: () => void;
+  placeholder?: string;
+  theme: Theme;
+  errorLine?: number | null;
+}
+
+// ---- Dark theme ----
+
+const darkTheme = EditorView.theme(
+  {
+    "&": {
+      backgroundColor: "#1e1e1e",
+      color: "#d4d4d4",
+    },
+    ".cm-content": { caretColor: "#fff" },
+    ".cm-cursor": { borderLeftColor: "#fff" },
+    ".cm-gutters": {
+      backgroundColor: "#1e1e1e",
+      color: "#858585",
+      border: "none",
+    },
+    ".cm-activeLineGutter": { backgroundColor: "#2a2a2a" },
+    ".cm-activeLine": { backgroundColor: "#2a2a2a" },
+    ".cm-errorLine": { backgroundColor: "rgba(255, 0, 0, 0.15)" },
+  },
+  { dark: true },
+);
+
+const darkHighlight = HighlightStyle.define([
+  { tag: tags.keyword, color: "#569cd6" },
+  { tag: tags.string, color: "#ce9178" },
+  { tag: tags.comment, color: "#6a9955" },
+  { tag: tags.number, color: "#b5cea8" },
+  { tag: tags.operator, color: "#d4d4d4" },
+  { tag: tags.punctuation, color: "#d4d4d4" },
+  { tag: tags.variableName, color: "#9cdcfe" },
+  { tag: tags.bracket, color: "#ffd700" },
+]);
+
+// ---- Light theme ----
+
+const lightTheme = EditorView.theme({
+  "&": {
+    backgroundColor: "#ffffff",
+    color: "#1e1e1e",
+  },
+  ".cm-content": { caretColor: "#000" },
+  ".cm-cursor": { borderLeftColor: "#000" },
+  ".cm-gutters": {
+    backgroundColor: "#fff",
+    color: "#999",
+    border: "none",
+  },
+  ".cm-activeLineGutter": { backgroundColor: "#e8e8e8" },
+  ".cm-activeLine": { backgroundColor: "#e8e8e8" },
+  ".cm-errorLine": { backgroundColor: "rgba(255, 0, 0, 0.1)" },
+});
+
+const lightHighlight = HighlightStyle.define([
+  { tag: tags.keyword, color: "#0000ff" },
+  { tag: tags.string, color: "#a31515" },
+  { tag: tags.comment, color: "#008000" },
+  { tag: tags.number, color: "#098658" },
+  { tag: tags.operator, color: "#1e1e1e" },
+  { tag: tags.punctuation, color: "#1e1e1e" },
+  { tag: tags.variableName, color: "#001080" },
+  { tag: tags.bracket, color: "#af00db" },
+]);
+
+// ---- Error line decoration ----
+
+const errorLineDeco = Decoration.line({ class: "cm-errorLine" });
+
+const getErrorLineExtension = (
+  errorLine: number | null | undefined,
+  doc: { line(n: number): { from: number }; lines: number },
+): Extension => {
+  if (!errorLine || errorLine < 1 || errorLine > doc.lines) {
+    return EditorView.decorations.of(Decoration.none);
+  }
+  const line = doc.line(errorLine);
+  return EditorView.decorations.of(
+    Decoration.set([errorLineDeco.range(line.from)]),
+  );
+};
+
+// ---- Helpers ----
+
+const getThemeExtensions = (theme: Theme) => {
+  if (theme === "dark") {
+    return [darkTheme, syntaxHighlighting(darkHighlight)];
+  }
+  return [lightTheme, syntaxHighlighting(lightHighlight)];
+};
+
+const CodeMirrorEditor = ({
+  value,
+  onChange,
+  onKeyboardSubmit,
+  placeholder,
+  theme,
+  errorLine,
+}: CodeMirrorEditorProps) => {
+  const containerRef = useRef<HTMLDivElement>(null);
+  const viewRef = useRef<EditorView | null>(null);
+  const onChangeRef = useRef(onChange);
+  const onKeyboardSubmitRef = useRef(onKeyboardSubmit);
+  const themeCompartmentRef = useRef(new Compartment());
+  const errorLineCompartmentRef = useRef(new Compartment());
+
+  onChangeRef.current = onChange;
+  onKeyboardSubmitRef.current = onKeyboardSubmit;
+
+  useEffect(() => {
+    if (!containerRef.current) {
+      return;
+    }
+
+    const themeCompartment = themeCompartmentRef.current;
+
+    const view = new EditorView({
+      state: EditorState.create({
+        doc: value,
+        extensions: [
+          keymap.of([
+            {
+              key: "Mod-Enter",
+              run: () => {
+                onKeyboardSubmitRef.current?.();
+                return true;
+              },
+            },
+            // historyKeymap binds Mod-Shift-z only on Mac; add it for all platforms
+            { key: "Mod-Shift-z", run: redo, preventDefault: true },
+          ]),
+          EditorView.updateListener.of((update) => {
+            if (update.docChanged) {
+              onChangeRef.current(update.state.doc.toString());
+            }
+          }),
+          history(),
+          keymap.of([...defaultKeymap, ...historyKeymap]),
+          lineNumbers(),
+          EditorView.lineWrapping,
+          themeCompartment.of(getThemeExtensions(theme)),
+          errorLineCompartmentRef.current.of([]),
+          mermaidLite(),
+          drawSelection({ drawRangeCursor: true }),
+          ...(placeholder ? [cmPlaceholder(placeholder)] : []),
+        ],
+      }),
+      parent: containerRef.current,
+    });
+
+    viewRef.current = view;
+    view.focus();
+
+    return () => {
+      view.destroy();
+      viewRef.current = null;
+    };
+    // eslint-disable-next-line react-hooks/exhaustive-deps
+  }, []);
+
+  // Swap theme dynamically via compartment
+  useEffect(() => {
+    const view = viewRef.current;
+    if (!view) {
+      return;
+    }
+    view.dispatch({
+      effects: themeCompartmentRef.current.reconfigure(
+        getThemeExtensions(theme),
+      ),
+    });
+  }, [theme]);
+
+  // Update error line highlight
+  useEffect(() => {
+    const view = viewRef.current;
+    if (!view) {
+      return;
+    }
+    view.dispatch({
+      effects: errorLineCompartmentRef.current.reconfigure(
+        getErrorLineExtension(errorLine, view.state.doc),
+      ),
+    });
+  }, [errorLine]);
+
+  // Sync external value changes into EditorView
+  useEffect(() => {
+    const view = viewRef.current;
+    if (!view) {
+      return;
+    }
+    const currentDoc = view.state.doc.toString();
+    if (value !== currentDoc) {
+      view.dispatch({
+        changes: { from: 0, to: currentDoc.length, insert: value },
+      });
+    }
+  }, [value]);
+
+  return (
+    <div
+      ref={containerRef}
+      className="ttd-dialog-input ttd-dialog-input--codemirror"
+    />
+  );
+};
+
+export default CodeMirrorEditor;

packages/excalidraw/components/TTDDialog/MermaidToExcalidraw.tsx

@@ -17,6 +17,11 @@ import { TTDDialogOutput } from "./TTDDialogOutput";
 import { TTDDialogPanel } from "./TTDDialogPanel";
 import { TTDDialogPanels } from "./TTDDialogPanels";
 import { TTDDialogSubmitShortcut } from "./TTDDialogSubmitShortcut";
+import {
+  getMermaidErrorLineNumber,
+  isMermaidAutoFixableError,
+} from "./utils/mermaidError";
+import { getMermaidAutoFixCandidates } from "./utils/mermaidAutoFix";
 import {
   convertMermaidToExcalidraw,
   insertToEditor,
@@ -33,6 +38,27 @@ const MERMAID_EXAMPLE =
   "flowchart TD\n A[Christmas] -->|Get money| B(Go shopping)\n B --> C{Let me think}\n C -->|One| D[Laptop]\n C -->|Two| E[iPhone]\n C -->|Three| F[Car]";
 
 const debouncedSaveMermaidDefinition = debounce(saveMermaidDataToStorage, 300);
+const AUTO_FIX_DEBOUNCE_MS = 500;
+const AUTO_FIX_MAX_DEPTH = 4;
+const AUTO_FIX_MAX_CANDIDATES = 30;
+
+const getErrorMessage = (error: unknown): string => {
+  if (error instanceof Error) {
+    return error.message;
+  }
+  if (typeof error === "string") {
+    return error;
+  }
+  if (
+    error &&
+    typeof error === "object" &&
+    "message" in error &&
+    typeof (error as { message?: unknown }).message === "string"
+  ) {
+    return (error as { message: string }).message;
+  }
+  return "";
+};
 
 const MermaidToExcalidraw = ({
   mermaidToExcalidrawLib,
@@ -46,8 +72,16 @@ const MermaidToExcalidraw = ({
       EditorLocalStorage.get<string>(EDITOR_LS_KEYS.MERMAID_TO_EXCALIDRAW) ||
       MERMAID_EXAMPLE,
   );
-  const deferredText = useDeferredValue(text.trim());
+  const deferredText = useDeferredValue(text);
   const [error, setError] = useState<Error | null>(null);
+  const [autoFixCandidate, setAutoFixCandidate] = useState<string | null>(null);
+
+  const errorLine = (() => {
+    if (!error?.message) {
+      return null;
+    }
+    return getMermaidErrorLineNumber(error.message, deferredText);
+  })();
 
   const canvasRef = useRef<HTMLDivElement>(null);
   const data = useRef<{
@@ -61,7 +95,7 @@ const MermaidToExcalidraw = ({
   useEffect(() => {
     const doRender = async () => {
       try {
-        if (!deferredText) {
+        if (!deferredText.trim()) {
           resetPreview({ canvasRef, setError });
           return;
         }
@@ -98,6 +132,88 @@ const MermaidToExcalidraw = ({
     [],
   );
 
+  useEffect(() => {
+    const errorMessage = error?.message ?? "";
+    const sourceText = deferredText;
+    const shouldTryAutoFix =
+      isActive &&
+      isMermaidAutoFixableError(errorMessage) &&
+      !!sourceText.trim() &&
+      mermaidToExcalidrawLib.loaded;
+
+    if (!shouldTryAutoFix) {
+      setAutoFixCandidate(null);
+      return;
+    }
+
+    const candidates = getMermaidAutoFixCandidates(sourceText, errorMessage);
+    if (!candidates.length) {
+      setAutoFixCandidate(null);
+      return;
+    }
+
+    let cancelled = false;
+    const timer = setTimeout(async () => {
+      try {
+        const api = await mermaidToExcalidrawLib.api;
+        const seen = new Set<string>([sourceText]);
+        const queue = candidates.map((candidate) => ({
+          text: candidate,
+          depth: 1,
+        }));
+
+        let triedCandidates = 0;
+
+        while (queue.length > 0 && triedCandidates < AUTO_FIX_MAX_CANDIDATES) {
+          const current = queue.shift();
+          if (!current || seen.has(current.text)) {
+            continue;
+          }
+          seen.add(current.text);
+          triedCandidates += 1;
+
+          try {
+            await api.parseMermaidToExcalidraw(current.text);
+            if (!cancelled) {
+              setAutoFixCandidate(current.text);
+            }
+            return;
+          } catch (candidateError) {
+            if (current.depth >= AUTO_FIX_MAX_DEPTH) {
+              continue;
+            }
+            const nextErrorMessage = getErrorMessage(candidateError);
+            if (!nextErrorMessage) {
+              continue;
+            }
+            const nextCandidates = getMermaidAutoFixCandidates(
+              current.text,
+              nextErrorMessage,
+            );
+            for (const nextCandidate of nextCandidates) {
+              if (!seen.has(nextCandidate)) {
+                queue.push({
+                  text: nextCandidate,
+                  depth: current.depth + 1,
+                });
+              }
+            }
+          }
+        }
+      } catch {
+        // ignore auto-fix probe errors
+      }
+      if (!cancelled) {
+        setAutoFixCandidate(null);
+      }
+    }, AUTO_FIX_DEBOUNCE_MS);
+
+    return () => {
+      cancelled = true;
+      clearTimeout(timer);
+    };
+  }, [deferredText, error?.message, isActive, mermaidToExcalidrawLib]);
+
   const onInsertToEditor = () => {
     insertToEditor({
       app,
@@ -107,21 +223,53 @@ const MermaidToExcalidraw = ({
     });
   };
 
+  const onApplyAutoFix = () => {
+    if (!autoFixCandidate) {
+      return;
+    }
+    setText(autoFixCandidate);
+  };
+
   return (
     <>
       <div className="ttd-dialog-desc">
         <Trans
           i18nKey="mermaid.description"
           flowchartLink={(el) => (
-            <a href="https://mermaid.js.org/syntax/flowchart.html">{el}</a>
+            <a
+              href="https://mermaid.js.org/syntax/flowchart.html"
+              target="_blank"
+              rel="noreferrer"
+            >
+              {el}
+            </a>
           )}
           sequenceLink={(el) => (
-            <a href="https://mermaid.js.org/syntax/sequenceDiagram.html">
+            <a
+              href="https://mermaid.js.org/syntax/sequenceDiagram.html"
+              target="_blank"
+              rel="noreferrer"
+            >
               {el}
             </a>
           )}
           classLink={(el) => (
-            <a href="https://mermaid.js.org/syntax/classDiagram.html">{el}</a>
+            <a
+              href="https://mermaid.js.org/syntax/classDiagram.html"
+              target="_blank"
+              rel="noreferrer"
+            >
+              {el}
+            </a>
+          )}
+          erdLink={(el) => (
+            <a
+              href="https://mermaid.js.org/syntax/entityRelationshipDiagram.html"
+              target="_blank"
+              rel="noreferrer"
+            >
+              {el}
+            </a>
           )}
         />
       </div>
@@ -130,7 +278,8 @@ const MermaidToExcalidraw = ({
           <TTDDialogInput
             input={text}
             placeholder={t("mermaid.inputPlaceholder")}
-            onChange={(event) => setText(event.target.value)}
+            onChange={(value) => setText(value)}
+            errorLine={errorLine}
             onKeyboardSubmit={() => {
               onInsertToEditor();
             }}
@@ -153,6 +302,9 @@ const MermaidToExcalidraw = ({
             canvasRef={canvasRef}
             loaded={mermaidToExcalidrawLib.loaded}
             error={error}
+            sourceText={text}
+            autoFixAvailable={!!autoFixCandidate}
+            onApplyAutoFix={onApplyAutoFix}
           />
         </TTDDialogPanel>
       </TTDDialogPanels>

packages/excalidraw/components/TTDDialog/TTDDialog.scss

@@ -219,6 +219,49 @@ $fullScreenModalBreakpoint: 600px;
     }
   }
 
+  .ttd-dialog-input--loading {
+    display: flex;
+    align-items: center;
+    justify-content: center;
+  }
+
+  .ttd-dialog-input--codemirror {
+    padding: 0;
+    overflow: hidden;
+    // Override height:100% from .ttd-dialog-input — use flex sizing
+    // so the editor fills remaining space without overflowing the panel
+    height: 0;
+    flex: 1 1 0;
+    min-height: 0;
+
+    .cm-editor {
+      height: 100%;
+      font-family: monospace;
+
+      &.cm-focused {
+        outline: none;
+      }
+    }
+
+    .cm-scroller {
+      padding: 0.85rem 0;
+      overflow: auto;
+    }
+
+    .cm-gutters {
+      padding-left: 0.25rem;
+    }
+
+    .cm-content {
+      padding: 0;
+    }
+
+    .cm-placeholder {
+      color: var(--color-gray-40);
+      font-style: italic;
+    }
+  }
+
   .ttd-dialog-output-wrapper {
     display: flex;
     flex-direction: column;
@@ -331,14 +374,55 @@ $fullScreenModalBreakpoint: 600px;
       margin-top: 0.25rem;
     }
 
+    .ttd-dialog-output-error-summary {
+      width: 100%;
+      max-width: 640px;
+      color: var(--color-gray-50);
+      font-size: 0.9rem;
+      text-align: left;
+
+      &__headline {
+        font-weight: 600;
+        color: var(--color-gray-60);
+      }
+
+      &__label {
+        margin-top: 0.35rem;
+        font-weight: 500;
+      }
+
+      &__causes {
+        margin: 0.35rem 0 0;
+        padding-left: 2rem;
+      }
+    }
+
     .ttd-dialog-output-error-message {
       text-align: left;
       font-weight: 400;
       color: var(--color-gray-50);
       word-break: break-word;
       white-space: pre-wrap;
-      max-width: 100%;
+      max-width: 640px;
+      width: 100%;
       font-family: monospace;
+
+      &__caret {
+        color: var(--color-danger);
+      }
+    }
+
+    .ttd-dialog-output-error-autofix-slot {
+      align-self: flex-start;
+      margin-top: 0.35rem;
+      min-height: 2.5rem;
+      display: flex;
+      align-items: flex-start;
+    }
+
+    .ttd-dialog-output-error-autofix {
+      margin-top: 0;
+      white-space: nowrap;
     }
   }
 

packages/excalidraw/components/TTDDialog/TTDDialogInput.tsx

@@ -1,28 +1,84 @@
-import { useEffect, useRef } from "react";
+import { useEffect, useRef, useState } from "react";
 
 import { EVENT, KEYS } from "@excalidraw/common";
 
-import type { ChangeEventHandler } from "react";
+import Spinner from "../Spinner";
+
+import { useUIAppState } from "../../context/ui-appState";
+
+import type { ComponentType } from "react";
+import type { CodeMirrorEditorProps } from "./CodeMirrorEditor";
 
 interface TTDDialogInputProps {
   input: string;
   placeholder: string;
-  onChange: ChangeEventHandler<HTMLTextAreaElement>;
+  onChange: (value: string) => void;
   onKeyboardSubmit?: () => void;
+  errorLine?: number | null;
 }
 
+type EditorState =
+  | { type: "loading" }
+  | { type: "ready"; component: ComponentType<CodeMirrorEditorProps> }
+  | { type: "fallback" };
+
+const SPINNER_DELAY_MS = 300;
+
 export const TTDDialogInput = ({
   input,
   placeholder,
   onChange,
   onKeyboardSubmit,
+  errorLine,
 }: TTDDialogInputProps) => {
   const ref = useRef<HTMLTextAreaElement>(null);
 
   const callbackRef = useRef(onKeyboardSubmit);
   callbackRef.current = onKeyboardSubmit;
 
+  const [editorState, setEditorState] = useState<EditorState>({
+    type: "loading",
+  });
+  const [showSpinner, setShowSpinner] = useState(false);
+
+  const { theme } = useUIAppState();
+
+  // Lazy-load CodeMirror editor
   useEffect(() => {
+    let cancelled = false;
+
+    const spinnerTimer = setTimeout(() => {
+      if (!cancelled) {
+        setShowSpinner(true);
+      }
+    }, SPINNER_DELAY_MS);
+
+    import("./CodeMirrorEditor")
+      .then((mod) => {
+        if (!cancelled) {
+          setEditorState({ type: "ready", component: mod.default });
+        }
+      })
+      .catch(() => {
+        if (!cancelled) {
+          setEditorState({ type: "fallback" });
+        }
+      })
+      .finally(() => {
+        clearTimeout(spinnerTimer);
+      });
+
+    return () => {
+      cancelled = true;
+      clearTimeout(spinnerTimer);
+    };
+  }, []);
+
+  // Keyboard shortcut + focus for textarea fallback
+  useEffect(() => {
+    if (editorState.type !== "fallback") {
+      return;
+    }
     if (!callbackRef.current) {
       return;
     }
@@ -40,15 +96,42 @@ export const TTDDialogInput = ({
         textarea.removeEventListener(EVENT.KEYDOWN, handleKeyDown);
       };
     }
-  }, []);
+  }, [editorState.type]);
 
-  return (
-    <textarea
-      className="ttd-dialog-input"
-      onChange={onChange}
-      value={input}
-      placeholder={placeholder}
-      ref={ref}
-    />
-  );
+  if (editorState.type === "ready") {
+    const CodeMirrorEditor = editorState.component;
+    return (
+      <CodeMirrorEditor
+        value={input}
+        onChange={onChange}
+        onKeyboardSubmit={onKeyboardSubmit}
+        placeholder={placeholder}
+        theme={theme}
+        errorLine={errorLine}
+      />
+    );
+  }
+
+  if (editorState.type === "fallback") {
+    return (
+      <textarea
+        className="ttd-dialog-input"
+        onChange={(e) => onChange(e.target.value)}
+        value={input}
+        placeholder={placeholder}
+        ref={ref}
+      />
+    );
+  }
+
+  // Loading state
+  if (showSpinner) {
+    return (
+      <div className="ttd-dialog-input ttd-dialog-input--loading">
+        <Spinner />
+      </div>
+    );
+  }
+
+  return null;
 };

packages/excalidraw/components/TTDDialog/TTDDialogOutput.tsx

@@ -1,14 +1,24 @@
 import clsx from "clsx";
 
+import { Button } from "../Button";
 import Spinner from "../Spinner";
 import { t } from "../../i18n";
 import { alertTriangleIcon } from "../icons";
 
+import {
+  formatMermaidParseErrorMessage,
+  getMermaidSyntaxErrorGuidance,
+  isMermaidCaretLine,
+} from "./utils/mermaidError";
+
 interface TTDDialogOutputProps {
   error: Error | null;
   canvasRef: React.RefObject<HTMLDivElement | null>;
   loaded: boolean;
   hideErrorDetails?: boolean;
+  sourceText?: string;
+  autoFixAvailable?: boolean;
+  onApplyAutoFix?: () => void;
 }
 
 export const TTDDialogOutput = ({
@@ -16,7 +26,24 @@ export const TTDDialogOutput = ({
   canvasRef,
   loaded,
   hideErrorDetails,
+  sourceText,
+  autoFixAvailable,
+  onApplyAutoFix,
 }: TTDDialogOutputProps) => {
+  const errorMessage = error
+    ? hideErrorDetails
+      ? t("chat.errors.mermaidParseError")
+      : formatMermaidParseErrorMessage(error.message)
+    : null;
+  const syntaxGuidance =
+    error && !hideErrorDetails
+      ? getMermaidSyntaxErrorGuidance(error.message, sourceText)
+      : null;
+  const showAutoFixButton =
+    !!autoFixAvailable && !!onApplyAutoFix && !hideErrorDetails;
+
+  const errorMessageLines = errorMessage?.split(/\r?\n/) ?? [];
+
   return (
     <div
       className={`ttd-dialog-output-wrapper ${
@@ -33,14 +60,48 @@ export const TTDDialogOutput = ({
             <div className="ttd-dialog-output-error-icon">
               {alertTriangleIcon}
             </div>
-            <div className="ttd-dialog-output-error-title">
-              {t("ttd.error")}
-            </div>
+            {syntaxGuidance && (
+              <div className="ttd-dialog-output-error-summary">
+                <div className="ttd-dialog-output-error-summary__headline">
+                  {syntaxGuidance.summary}
+                </div>
+                <div className="ttd-dialog-output-error-summary__label">
+                  Likely causes:
+                </div>
+                <ul className="ttd-dialog-output-error-summary__causes">
+                  {syntaxGuidance.likelyCauses.map((cause) => (
+                    <li key={cause}>{cause}</li>
+                  ))}
+                </ul>
+              </div>
+            )}
             <div className="ttd-dialog-output-error-message">
-              {hideErrorDetails
-                ? t("chat.errors.mermaidParseError")
-                : error.message}
+              {errorMessageLines.map((line, index) => (
+                <span
+                  key={`error-line-${index}`}
+                  className={
+                    isMermaidCaretLine(line)
+                      ? "ttd-dialog-output-error-message__caret"
+                      : undefined
+                  }
+                >
+                  {line}
+                  {index < errorMessageLines.length - 1 ? "\n" : ""}
+                </span>
+              ))}
             </div>
+            {!hideErrorDetails && (
+              <div className="ttd-dialog-output-error-autofix-slot">
+                {showAutoFixButton ? (
+                  <Button
+                    className="ttd-dialog-panel-button ttd-dialog-output-error-autofix"
+                    onSelect={onApplyAutoFix}
+                  >
+                    {t("mermaid.autoFixAvailable")}
+                  </Button>
+                ) : null}
+              </div>
+            )}
           </div>
         </div>
       )}

packages/excalidraw/components/TTDDialog/TTDDialogSubmitShortcut.tsx

@@ -1,4 +1,4 @@
-import { getShortcutKey } from "@excalidraw/excalidraw/shortcut";
+import { getShortcutKey } from "../../shortcut";
 
 export const TTDDialogSubmitShortcut = () => {
   return (

packages/excalidraw/components/TTDDialog/common.test.ts

@@ -0,0 +1,89 @@
+import { describe, expect, it, vi } from "vitest";
+
+import { convertMermaidToExcalidraw } from "./common";
+
+type ConvertMermaidArgs = Parameters<typeof convertMermaidToExcalidraw>[0];
+type ParseMermaidToExcalidraw = Awaited<
+  ConvertMermaidArgs["mermaidToExcalidrawLib"]["api"]
+>["parseMermaidToExcalidraw"];
+
+const createConvertArgs = (
+  mermaidDefinition: string,
+  parseMermaidToExcalidraw: ParseMermaidToExcalidraw,
+): ConvertMermaidArgs => {
+  const parent = document.createElement("div");
+  const canvas = document.createElement("div");
+  parent.appendChild(canvas);
+
+  return {
+    canvasRef: { current: canvas },
+    mermaidToExcalidrawLib: {
+      loaded: true,
+      api: Promise.resolve({ parseMermaidToExcalidraw }),
+    },
+    mermaidDefinition,
+    setError: vi.fn(),
+    data: {
+      current: {
+        elements: [],
+        files: null,
+      },
+    },
+    theme: "light",
+  };
+};
+
+describe("convertMermaidToExcalidraw", () => {
+  it("returns the original parse error when quote-normalized fallback also fails", async () => {
+    const originalError = new Error("Parse error on line 9: ...");
+    const fallbackError = new Error("Parse error on line 6: ...");
+
+    const parseMermaidToExcalidraw = vi
+      .fn<ParseMermaidToExcalidraw>()
+      .mockRejectedValueOnce(originalError)
+      .mockRejectedValueOnce(fallbackError);
+
+    const mermaidDefinition =
+      'graph TD\nA["One"]\nB["Two"]x\nC["Three"]\nD["Four"]';
+
+    const result = await convertMermaidToExcalidraw(
+      createConvertArgs(mermaidDefinition, parseMermaidToExcalidraw),
+    );
+
+    expect(parseMermaidToExcalidraw).toHaveBeenCalledTimes(2);
+    expect(parseMermaidToExcalidraw).toHaveBeenNthCalledWith(
+      1,
+      mermaidDefinition,
+    );
+    expect(parseMermaidToExcalidraw).toHaveBeenNthCalledWith(
+      2,
+      mermaidDefinition.replace(/"/g, "'"),
+    );
+
+    expect(result.success).toBe(false);
+    if (!result.success) {
+      expect(result.error).toBe(originalError);
+    }
+  });
+
+  it("does not retry quote normalization when the input has no double quotes", async () => {
+    const originalError = new Error("Parse error on line 9: ...");
+    const parseMermaidToExcalidraw = vi
+      .fn<ParseMermaidToExcalidraw>()
+      .mockRejectedValueOnce(originalError);
+
+    const mermaidDefinition = "graph TD\nA[One]\nB[Two]x";
+
+    const result = await convertMermaidToExcalidraw(
+      createConvertArgs(mermaidDefinition, parseMermaidToExcalidraw),
+    );
+
+    expect(parseMermaidToExcalidraw).toHaveBeenCalledTimes(1);
+    expect(parseMermaidToExcalidraw).toHaveBeenCalledWith(mermaidDefinition);
+
+    expect(result.success).toBe(false);
+    if (!result.success) {
+      expect(result.error).toBe(originalError);
+    }
+  });
+});

packages/excalidraw/components/TTDDialog/common.ts

@@ -1,4 +1,12 @@
-import { DEFAULT_EXPORT_PADDING, EDITOR_LS_KEYS } from "@excalidraw/common";
+import {
+  DEFAULT_EXPORT_PADDING,
+  EDITOR_LS_KEYS,
+  THEME,
+} from "@excalidraw/common";
+
+import { convertToExcalidrawElements } from "@excalidraw/element";
+
+import { exportToCanvas } from "@excalidraw/utils";
 
 import type {
   NonDeletedExcalidrawElement,
@@ -6,11 +14,6 @@ import type {
 } from "@excalidraw/element/types";
 
 import { EditorLocalStorage } from "../../data/EditorLocalStorage";
-import {
-  convertToExcalidrawElements,
-  exportToCanvas,
-  THEME,
-} from "../../index";
 
 import type { MermaidToExcalidrawLibProps } from "./types";
 
@@ -72,18 +75,26 @@ export const convertMermaidToExcalidraw = async ({
     const api = await mermaidToExcalidrawLib.api;
 
     try {
+      ret = await api.parseMermaidToExcalidraw(mermaidDefinition);
+    } catch (err: unknown) {
+      const originalParseError = err as Error;
+
+      if (!mermaidDefinition.includes('"')) {
+        return { success: false, error: originalParseError };
+      }
+
       try {
-        ret = await api.parseMermaidToExcalidraw(mermaidDefinition);
-      } catch (err: unknown) {
         ret = await api.parseMermaidToExcalidraw(
           mermaidDefinition.replace(/"/g, "'"),
         );
+      } catch {
+        // Keep the original error so line/column references stay aligned with
+        // the user's unmodified input.
+        return { success: false, error: originalParseError };
       }
-    } catch (err: unknown) {
-      return { success: false, error: err as Error };
     }
 
-    const { elements, files } = ret;
+    const { elements, files = {} } = ret;
     setError(null);
 
     data.current = {

packages/excalidraw/components/TTDDialog/mermaid-lang-lite.ts

@@ -0,0 +1,82 @@
+import { StreamLanguage } from "@codemirror/language";
+
+const mermaidStreamParser = StreamLanguage.define({
+  token(stream) {
+    // Comments: %%...
+    if (stream.match(/^%%.*$/)) {
+      return "comment";
+    }
+
+    // Strings
+    if (stream.match(/^"(?:[^"\\]|\\.)*"/)) {
+      return "string";
+    }
+
+    // Diagram type keywords (at start of line or after whitespace)
+    if (
+      stream.match(
+        /^(flowchart|graph|sequenceDiagram|classDiagram|stateDiagram|erDiagram|gantt|pie|mindmap|journey|gitGraph|timeline|quadrantChart|sankey|xychart)\b/i,
+      )
+    ) {
+      return "keyword";
+    }
+
+    // Direction keywords
+    if (stream.match(/^(TB|TD|BT|RL|LR)\b/)) {
+      return "keyword";
+    }
+
+    // Keywords
+    if (
+      stream.match(
+        /^(subgraph|end|participant|actor|loop|alt|else|opt|par|critical|break|rect|note|over|activate|deactivate|title|section|class|style|linkStyle|classDef|click)\b/i,
+      )
+    ) {
+      return "keyword";
+    }
+
+    // Arrows: -->, ---, -.->, ===>, etc.
+    if (stream.match(/^[-.=<>|ox]+>/)) {
+      return "operator";
+    }
+    if (stream.match(/^<[-.=<>|ox]+/)) {
+      return "operator";
+    }
+    if (stream.match(/^--+|\.\.+|==+/)) {
+      return "operator";
+    }
+
+    // Labels in brackets/parens: [text], (text), {text}, ((text)), etc.
+    if (stream.match(/^[[\](){}|<>]/)) {
+      return "bracket";
+    }
+
+    // Node IDs (alphanumeric)
+    if (stream.match(/^[A-Za-z_][A-Za-z0-9_]*/)) {
+      return "variableName";
+    }
+
+    // Numbers
+    if (stream.match(/^\d+(\.\d+)?/)) {
+      return "number";
+    }
+
+    // Punctuation
+    if (stream.match(/^[,:;]/)) {
+      return "punctuation";
+    }
+
+    // Skip whitespace
+    if (stream.eatSpace()) {
+      return null;
+    }
+
+    // Skip any other character
+    stream.next();
+    return null;
+  },
+});
+
+export function mermaidLite() {
+  return mermaidStreamParser;
+}

packages/excalidraw/components/TTDDialog/utils/TTDStreamFetch.ts

@@ -1,9 +1,6 @@
-import { RequestError } from "@excalidraw/excalidraw/errors";
+import { RequestError } from "../../../errors";
 
-import type {
-  LLMMessage,
-  TTTDDialog,
-} from "@excalidraw/excalidraw/components/TTDDialog/types";
+import type { LLMMessage, TTTDDialog } from "../types";
 
 interface RateLimitInfo {
   rateLimit?: number;

packages/excalidraw/components/TTDDialog/utils/mermaidAutoFix.test.ts

@@ -0,0 +1,116 @@
+import { describe, expect, it } from "vitest";
+
+import { getMermaidAutoFixCandidates } from "./mermaidAutoFix";
+
+describe("getMermaidAutoFixCandidates", () => {
+  it("suggests removing trailing token after a closed label shape", () => {
+    const sourceText = `graph TD
+  L3_TCP["TCP (Transmission Control Protocol)"]x
+  L3_UDP["UDP (User Datagram Protocol)"]`;
+
+    const errorMessage = `Parse error on line 2:
+...ission Control Protocol)"]x
+-----------------------------^
+Expecting 'SEMI', got 'NODE_STRING'`;
+
+    const candidates = getMermaidAutoFixCandidates(sourceText, errorMessage);
+
+    expect(candidates).toContain(`graph TD
+  L3_TCP["TCP (Transmission Control Protocol)"]
+  L3_UDP["UDP (User Datagram Protocol)"]`);
+  });
+
+  it("suggests appending missing end statements", () => {
+    const sourceText = `graph TD
+subgraph A
+  A1[Start]`;
+
+    const errorMessage = `Parse error on line 3:
+... A1[Start]
+-------------^
+Expecting 'end'`;
+
+    const candidates = getMermaidAutoFixCandidates(sourceText, errorMessage);
+
+    expect(candidates).toContain(`graph TD
+subgraph A
+  A1[Start]
+end`);
+  });
+
+  it("returns empty list for non-parse errors", () => {
+    expect(
+      getMermaidAutoFixCandidates("graph TD\nA-->B", "Network error"),
+    ).toEqual([]);
+  });
+
+  it("extracts line index from lexical error format too", () => {
+    const sourceText = `graph TD
+  subgraph Layers["X"]x
+  direction TB`;
+
+    const errorMessage = `Lexical error on line 2. Unrecognized text.
+...  subgraph Layers["X"]x        direction
+-----------------------^`;
+
+    const candidates = getMermaidAutoFixCandidates(sourceText, errorMessage);
+
+    expect(candidates).toContain(`graph TD
+  subgraph Layers["X"]
+  direction TB`);
+  });
+
+  it("removes extra > after edge label", () => {
+    const sourceText = `flowchart TD
+  A["User Input"] -->|text|> B["Tokenization"]
+  A["User Input"] -->|text|> B["Tokenization"]`;
+
+    const errorMessage = `Parse error on line 2:
+...A["User Input"] -->|text|> B["Tokenization"]
+---------------------------^
+Expecting 'NODE_STRING', got 'GT'`;
+
+    const candidates = getMermaidAutoFixCandidates(sourceText, errorMessage);
+
+    expect(candidates).toContain(`flowchart TD
+  A["User Input"] -->|text| B["Tokenization"]
+  A["User Input"] -->|text| B["Tokenization"]`);
+  });
+
+  it("suggests removing the last invalid deactivate for participant errors", () => {
+    const sourceText = `sequenceDiagram
+  participant QAEngineer as QA
+  activate QA
+  QA->>QA: Verifies Fix
+  deactivate QA
+  QA->>QA: Verifies Again
+  deactivate QA`;
+
+    const errorMessage = "Trying to inactivate an inactive participant (QA)";
+
+    const candidates = getMermaidAutoFixCandidates(sourceText, errorMessage);
+
+    expect(candidates).toContain(`sequenceDiagram
+  participant QAEngineer as QA
+  activate QA
+  QA->>QA: Verifies Fix
+  deactivate QA
+  QA->>QA: Verifies Again`);
+  });
+
+  it("adds a fallback candidate that removes all invalid deactivations", () => {
+    const sourceText = `sequenceDiagram
+  participant QAEngineer as QA
+  deactivate QA
+  QA->>QA: Verifies Fix
+  deactivate QA`;
+
+    const errorMessage = "Trying to inactivate an inactive participant (QA)";
+
+    const candidates = getMermaidAutoFixCandidates(sourceText, errorMessage);
+
+    expect(candidates).toContain(`sequenceDiagram
+  participant QAEngineer as QA
+  QA->>QA: Verifies Fix`);
+  });
+});

packages/excalidraw/components/TTDDialog/utils/mermaidAutoFix.ts

@@ -0,0 +1,175 @@
+import {
+  getMermaidErrorLineNumber,
+  getMermaidInactiveParticipant,
+  isMermaidAutoFixableError,
+  isMermaidParseSyntaxError,
+} from "./mermaidError";
+
+const getErrorLineIndex = (message: string, sourceText: string) => {
+  const lineNumber = getMermaidErrorLineNumber(message, sourceText);
+  if (lineNumber == null) {
+    return null;
+  }
+  return lineNumber - 1;
+};
+
+const replaceLineAt = (
+  lines: string[],
+  index: number,
+  transform: (line: string) => string,
+) => {
+  if (index < 0 || index >= lines.length) {
+    return null;
+  }
+  const nextLine = transform(lines[index]);
+  if (nextLine === lines[index]) {
+    return null;
+  }
+  const nextLines = [...lines];
+  nextLines[index] = nextLine;
+  return nextLines.join("\n");
+};
+
+const stripTrailingTokenAfterShape = (line: string) => {
+  const alphaTailMatch = line.match(
+    /^(.*(?:\[[^\]]*]|\([^)]*\)|\{[^}]*}|"(?:[^"]*)"|'(?:[^']*)'))([A-Za-z]+)\s*$/,
+  );
+  if (alphaTailMatch) {
+    return alphaTailMatch[1];
+  }
+
+  const punctuationTailMatch = line.match(
+    /^(.*(?:\[[^\]]*]|\([^)]*\)|\{[^}]*}|"(?:[^"]*)"|'(?:[^']*)'))([,;:])\s*$/,
+  );
+  if (punctuationTailMatch) {
+    return punctuationTailMatch[1];
+  }
+
+  return line;
+};
+
+const removeExtraArrowheadAfterEdgeLabel = (line: string) => {
+  // Common typo in generated Mermaid: `-->|label|> Target` (extra `>`).
+  // Convert it to `-->|label| Target`.
+  return line.replace(/(\|[^|\n]+\|)\s*>\s*(?=[A-Za-z0-9_("[{'`])/g, "$1 ");
+};
+
+const escapeRegExp = (value: string) =>
+  value.replace(/[.*+?^${}()|[\]\\]/g, "\\$&");
+
+const removeLastDeactivateForParticipant = (
+  sourceText: string,
+  participant: string,
+) => {
+  const pattern = new RegExp(
+    `^\\s*deactivate\\s+${escapeRegExp(participant)}(?:\\s+%%.*)?\\s*$`,
+  );
+  const lines = sourceText.split(/\r?\n/);
+
+  for (let index = lines.length - 1; index >= 0; index--) {
+    if (pattern.test(lines[index])) {
+      return lines.filter((_, lineIndex) => lineIndex !== index).join("\n");
+    }
+  }
+
+  return null;
+};
+
+const removeAllDeactivateForParticipant = (
+  sourceText: string,
+  participant: string,
+) => {
+  const pattern = new RegExp(
+    `^\\s*deactivate\\s+${escapeRegExp(participant)}(?:\\s+%%.*)?\\s*$`,
+  );
+  const lines = sourceText.split(/\r?\n/);
+  let removedAny = false;
+  const remainingLines = lines.filter((line) => {
+    if (!pattern.test(line)) {
+      return true;
+    }
+    removedAny = true;
+    return false;
+  });
+
+  return removedAny ? remainingLines.join("\n") : null;
+};
+
+const appendMissingEnds = (sourceText: string) => {
+  const subgraphCount = (sourceText.match(/^\s*subgraph\b/gm) || []).length;
+  const endCount = (sourceText.match(/^\s*end\s*$/gm) || []).length;
+  const missingCount = subgraphCount - endCount;
+
+  if (missingCount <= 0) {
+    return null;
+  }
+
+  const endings = Array.from({ length: missingCount }, () => "end").join("\n");
+  return `${sourceText.trimEnd()}\n${endings}`;
+};
+
+const normalizeSmartQuotes = (sourceText: string) =>
+  sourceText.replace(/[“”]/g, '"').replace(/[‘’]/g, "'");
+
+export const getMermaidAutoFixCandidates = (
+  sourceText: string,
+  errorMessage: string,
+) => {
+  if (!isMermaidAutoFixableError(errorMessage) || !sourceText.trim()) {
+    return [];
+  }
+
+  const candidates: string[] = [];
+  const seen = new Set<string>();
+  const addCandidate = (candidate: string | null) => {
+    if (!candidate || candidate === sourceText || seen.has(candidate)) {
+      return;
+    }
+    seen.add(candidate);
+    candidates.push(candidate);
+  };
+
+  const inactiveParticipant = getMermaidInactiveParticipant(errorMessage);
+  if (inactiveParticipant) {
+    addCandidate(
+      removeLastDeactivateForParticipant(sourceText, inactiveParticipant),
+    );
+    // Fallback for repeated invalid inactivations in one diagram.
+    addCandidate(
+      removeAllDeactivateForParticipant(sourceText, inactiveParticipant),
+    );
+  }
+
+  if (isMermaidParseSyntaxError(errorMessage)) {
+    const lines = sourceText.split(/\r?\n/);
+    const errorLineIndex = getErrorLineIndex(errorMessage, sourceText);
+    const lineIndexesToTry =
+      errorLineIndex == null
+        ? []
+        : [errorLineIndex, errorLineIndex - 1, errorLineIndex + 1];
+
+    for (const lineIndex of lineIndexesToTry) {
+      addCandidate(
+        replaceLineAt(lines, lineIndex, (line) =>
+          stripTrailingTokenAfterShape(line),
+        ),
+      );
+      addCandidate(
+        replaceLineAt(lines, lineIndex, (line) =>
+          removeExtraArrowheadAfterEdgeLabel(line),
+        ),
+      );
+    }
+
+    // Also try full-text replacement so repeated occurrences on other lines
+    // are fixed together in a single candidate.
+    addCandidate(removeExtraArrowheadAfterEdgeLabel(sourceText));
+
+    addCandidate(appendMissingEnds(sourceText));
+
+    const normalizedQuotes = normalizeSmartQuotes(sourceText);
+    addCandidate(normalizedQuotes === sourceText ? null : normalizedQuotes);
+  }
+
+  return candidates;
+};

packages/excalidraw/components/TTDDialog/utils/mermaidError.test.ts

@@ -0,0 +1,155 @@
+import { describe, expect, it } from "vitest";
+
+import {
+  formatMermaidParseErrorMessage,
+  getMermaidErrorLineNumber,
+  getMermaidInactiveParticipant,
+  getMermaidSyntaxErrorGuidance,
+  isMermaidAutoFixableError,
+  isMermaidParseSyntaxError,
+  isMermaidCaretLine,
+} from "./mermaidError";
+
+describe("formatMermaidParseErrorMessage", () => {
+  it("strips the noisy Expecting clause from Mermaid parse errors", () => {
+    const message = `Parse error on line 6:
+... Control Protocol)"]x          L3_UDP
+----------------------^
+Expecting 'SEMI', 'NEWLINE', 'SPACE', got 'NODE_STRING'`;
+
+    expect(formatMermaidParseErrorMessage(message)).toBe(`Parse error on line 6:
+... Control Protocol)"]x          L3_UDP
+----------------------^`);
+  });
+
+  it("keeps Mermaid parse errors unchanged when no Expecting clause exists", () => {
+    const message = `Parse error on line 3:
+... some snippet
+----^`;
+
+    expect(formatMermaidParseErrorMessage(message)).toBe(message);
+  });
+
+  it("does not modify non-Mermaid parse messages", () => {
+    const message =
+      "Unexpected token while parsing JSON. Expecting value at position 10.";
+
+    expect(formatMermaidParseErrorMessage(message)).toBe(message);
+  });
+});
+
+describe("isMermaidCaretLine", () => {
+  it("returns true for Mermaid caret lines", () => {
+    expect(isMermaidCaretLine("-----------------------^")).toBe(true);
+  });
+
+  it("returns false for regular lines", () => {
+    expect(isMermaidCaretLine(`... Control Protocol)"]x`)).toBe(false);
+  });
+});
+
+describe("isMermaidParseSyntaxError", () => {
+  it("returns true for Mermaid parser syntax errors", () => {
+    expect(isMermaidParseSyntaxError("Parse error on line 6: ...")).toBe(true);
+  });
+
+  it("returns true for Mermaid lexical syntax errors", () => {
+    expect(
+      isMermaidParseSyntaxError("Lexical error on line 2. Unrecognized text."),
+    ).toBe(true);
+  });
+
+  it("returns false for non-parse errors", () => {
+    expect(isMermaidParseSyntaxError("Network error")).toBe(false);
+  });
+});
+
+describe("isMermaidAutoFixableError", () => {
+  it("returns true for Mermaid parser syntax errors", () => {
+    expect(isMermaidAutoFixableError("Parse error on line 6: ...")).toBe(true);
+  });
+
+  it("returns true for inactive participant runtime errors", () => {
+    expect(
+      isMermaidAutoFixableError(
+        "Trying to inactivate an inactive participant (QA)",
+      ),
+    ).toBe(true);
+  });
+
+  it("returns false for non-fixable errors", () => {
+    expect(isMermaidAutoFixableError("Network error")).toBe(false);
+  });
+});
+
+describe("getMermaidInactiveParticipant", () => {
+  it("extracts the participant id from inactive participant errors", () => {
+    expect(
+      getMermaidInactiveParticipant(
+        "Trying to inactivate an inactive participant (QA)",
+      ),
+    ).toBe("QA");
+  });
+
+  it("returns null for unrelated errors", () => {
+    expect(
+      getMermaidInactiveParticipant("Parse error on line 3: ..."),
+    ).toBeNull();
+  });
+});
+
+describe("getMermaidErrorLineNumber", () => {
+  it("extracts line number from parse error format", () => {
+    expect(getMermaidErrorLineNumber("Parse error on line 6: ...")).toBe(6);
+  });
+
+  it("extracts line number from lexical error format", () => {
+    expect(
+      getMermaidErrorLineNumber("Lexical error on line 2. Unrecognized text."),
+    ).toBe(2);
+  });
+
+  it("returns null for messages without Mermaid line details", () => {
+    expect(getMermaidErrorLineNumber("Network error")).toBeNull();
+  });
+
+  it("infers line from inactive participant errors when source text is provided", () => {
+    const sourceText = `sequenceDiagram
+  participant QA
+  deactivate QA
+  QA->>QA: Verifies Fix
+  deactivate QA`;
+
+    expect(
+      getMermaidErrorLineNumber(
+        "Trying to inactivate an inactive participant (QA)",
+        sourceText,
+      ),
+    ).toBe(5);
+  });
+});
+
+describe("getMermaidSyntaxErrorGuidance", () => {
+  it("returns summary and likely causes for Mermaid parse errors", () => {
+    const message = `Parse error on line 6:
+... Control Protocol)"]x
+----------------------^`;
+
+    const source = `graph TD
+subgraph Layers["X"]
+  L3_TCP["TCP (Transmission Control Protocol)"]x`;
+
+    expect(getMermaidSyntaxErrorGuidance(message, source)).toEqual({
+      summary: "Syntax error near line 6.",
+      likelyCauses: expect.arrayContaining([
+        "A block is missing an `end` statement.",
+      ]),
+    });
+  });
+
+  it("returns null for non-parse errors", () => {
+    expect(
+      getMermaidSyntaxErrorGuidance("Network error", "graph TD"),
+    ).toBeNull();
+  });
+});

packages/excalidraw/components/TTDDialog/utils/mermaidError.ts

@@ -0,0 +1,133 @@
+const MERMAID_SYNTAX_ERROR_LINE = /(?:Parse|Lexical) error on line (\d+)[.:]/i;
+const MERMAID_INACTIVE_PARTICIPANT_ERROR =
+  /Trying to inactivate an inactive participant \((.+)\)/i;
+const MERMAID_CARET_LINE = /^\s*-+\^\s*$/;
+
+export const isMermaidParseSyntaxError = (message: string) =>
+  MERMAID_SYNTAX_ERROR_LINE.test(message);
+
+export const isMermaidAutoFixableError = (message: string) =>
+  isMermaidParseSyntaxError(message) ||
+  MERMAID_INACTIVE_PARTICIPANT_ERROR.test(message);
+
+export const isMermaidCaretLine = (line: string) =>
+  MERMAID_CARET_LINE.test(line);
+
+export const getMermaidInactiveParticipant = (
+  message: string,
+): string | null => {
+  const match = message.match(MERMAID_INACTIVE_PARTICIPANT_ERROR);
+  if (!match?.[1]) {
+    return null;
+  }
+  return match[1].trim();
+};
+
+const escapeRegExp = (value: string) =>
+  value.replace(/[.*+?^${}()|[\]\\]/g, "\\$&");
+
+const getInactiveParticipantLineNumber = (
+  message: string,
+  sourceText: string,
+): number | null => {
+  const participant = getMermaidInactiveParticipant(message);
+  if (!participant) {
+    return null;
+  }
+
+  const deactivatePattern = new RegExp(
+    `^\\s*deactivate\\s+${escapeRegExp(participant)}(?:\\s+%%.*)?\\s*$`,
+  );
+  const lines = sourceText.split(/\r?\n/);
+  for (let index = lines.length - 1; index >= 0; index--) {
+    if (deactivatePattern.test(lines[index])) {
+      return index + 1;
+    }
+  }
+  return null;
+};
+
+export const getMermaidErrorLineNumber = (
+  message: string,
+  sourceText?: string,
+): number | null => {
+  const match = message.match(MERMAID_SYNTAX_ERROR_LINE);
+  if (!match) {
+    if (!sourceText) {
+      return null;
+    }
+    return getInactiveParticipantLineNumber(message, sourceText);
+  }
+  return Number.parseInt(match[1], 10);
+};
+
+const countMatches = (text: string, re: RegExp) =>
+  (text.match(re) || []).length;
+
+export const getMermaidSyntaxErrorGuidance = (
+  message: string,
+  sourceText?: string,
+): { summary: string; likelyCauses: string[] } | null => {
+  if (!isMermaidParseSyntaxError(message)) {
+    return null;
+  }
+
+  const errorLine = getMermaidErrorLineNumber(message, sourceText);
+  const summary = errorLine
+    ? `Syntax error near line ${errorLine}.`
+    : "Syntax error in Mermaid diagram.";
+
+  const likelyCauses: string[] = [];
+
+  if (sourceText) {
+    const openBrackets = countMatches(sourceText, /\[/g);
+    const closeBrackets = countMatches(sourceText, /\]/g);
+    if (openBrackets !== closeBrackets) {
+      likelyCauses.push("Unbalanced square brackets in a node label.");
+    }
+
+    const openParens = countMatches(sourceText, /\(/g);
+    const closeParens = countMatches(sourceText, /\)/g);
+    if (openParens !== closeParens) {
+      likelyCauses.push("Unbalanced parentheses in a node shape.");
+    }
+
+    const openBraces = countMatches(sourceText, /\{/g);
+    const closeBraces = countMatches(sourceText, /\}/g);
+    if (openBraces !== closeBraces) {
+      likelyCauses.push("Unbalanced braces in a decision node.");
+    }
+
+    const subgraphCount = countMatches(sourceText, /^\s*subgraph\b/gm);
+    const endCount = countMatches(sourceText, /^\s*end\s*$/gm);
+    if (subgraphCount > endCount) {
+      likelyCauses.push("A block is missing an `end` statement.");
+    }
+  }
+
+  if (/got 'NODE_STRING'/.test(message) || /got 'PS'/.test(message)) {
+    likelyCauses.push(
+      "An extra character/token may appear after a node or label definition.",
+    );
+  }
+
+  if (likelyCauses.length === 0) {
+    likelyCauses.push(
+      "A node or edge line is malformed (missing/extra delimiters).",
+    );
+    likelyCauses.push("A block (`subgraph`, `class`, etc.) may be incomplete.");
+  }
+
+  return {
+    summary,
+    likelyCauses: [...new Set(likelyCauses)],
+  };
+};
+
+export const formatMermaidParseErrorMessage = (message: string) => {
+  if (!isMermaidParseSyntaxError(message)) {
+    return message;
+  }
+
+  return message.replace(/\n\s*Expecting[\s\S]*$/, "").trimEnd();
+};

packages/excalidraw/components/Toast.scss

@@ -1,35 +1,51 @@
-@use "../css/variables.module" as *;
-
 .excalidraw {
   .Toast {
     $closeButtonSize: 1.2rem;
     $closeButtonPadding: 0.4rem;
 
-    animation: fade-in 0.5s;
-    background-color: var(--button-gray-1);
-    border-radius: 4px;
-    bottom: 10px;
+    animation: Toast-fade-in 0.5s;
+    min-width: 220px;
+    max-width: min(360px, calc(100vw - 32px));
+    border-radius: var(--border-radius-lg);
+    border: 1px solid var(--default-border-color);
+    background-color: var(--island-bg-color);
+    color: var(--text-primary-color);
+    padding: 0.5rem 0.75rem;
+    box-shadow: 0 0 0 1px var(--color-surface-lowest);
     box-sizing: border-box;
     cursor: default;
-    left: 50%;
-    margin-left: -150px;
-    padding: 4px 0;
-    position: absolute;
-    text-align: center;
-    width: 300px;
-    z-index: 999999;
+    pointer-events: none;
 
     .Toast__message {
+      font-family: var(--ui-font);
+      font-size: 0.75rem;
+      line-height: 1.25rem;
+      text-align: center;
       padding: 0 $closeButtonSize + ($closeButtonPadding);
-      color: var(--popup-text-color);
       white-space: pre-wrap;
     }
 
+    .Toast__progress-bar {
+      margin-top: 0.35rem;
+      width: 100%;
+      height: 4px;
+      border-radius: 999px;
+      background-color: var(--button-gray-2);
+      overflow: hidden;
+    }
+
+    .Toast__progress-bar-fill {
+      height: 100%;
+      border-radius: inherit;
+      background-color: var(--color-primary);
+    }
+
     .close {
       position: absolute;
       top: 0;
       right: 0;
       padding: $closeButtonPadding;
+      pointer-events: auto;
 
       .ToolIcon__icon {
         width: $closeButtonSize;
@@ -38,7 +54,7 @@
     }
   }
 
-  @keyframes fade-in {
+  @keyframes Toast-fade-in {
     from {
       opacity: 0;
     }

packages/excalidraw/components/Toast.tsx

@@ -5,11 +5,22 @@ import { ToolButton } from "./ToolButton";
 
 import "./Toast.scss";
 
-import type { CSSProperties } from "react";
+import type { CSSProperties, ReactNode } from "react";
 
 const DEFAULT_TOAST_TIMEOUT = 5000;
 
-export const Toast = ({
+const ProgressBar = ({ progress }: { progress: number }) => (
+  <div className="Toast__progress-bar">
+    <div
+      className="Toast__progress-bar-fill"
+      style={{
+        width: `${Math.min(5, Math.round(progress * 100))}%`,
+      }}
+    />
+  </div>
+);
+
+const ToastComponent = ({
   message,
   onClose,
   closable = false,
@@ -17,7 +28,7 @@ export const Toast = ({
   duration = DEFAULT_TOAST_TIMEOUT,
   style,
 }: {
-  message: string;
+  message: ReactNode;
   onClose: () => void;
   closable?: boolean;
   duration?: number;
@@ -47,11 +58,12 @@ export const Toast = ({
   return (
     <div
       className="Toast"
+      role="status"
       onMouseEnter={onMouseEnter}
       onMouseLeave={onMouseLeave}
       style={style}
     >
-      <p className="Toast__message">{message}</p>
+      <div className="Toast__message">{message}</div>
       {closable && (
         <ToolButton
           icon={CloseIcon}
@@ -64,3 +76,5 @@ export const Toast = ({
     </div>
   );
 };
+
+export const Toast = Object.assign(ToastComponent, { ProgressBar });

packages/excalidraw/components/canvases/InteractiveCanvas.tsx

@@ -6,7 +6,6 @@ import {
   sceneCoordsToViewportCoords,
   type EditorInterface,
 } from "@excalidraw/common";
-import { AnimationController } from "@excalidraw/excalidraw/renderer/animation";
 
 import type {
   InteractiveCanvasRenderConfig,
@@ -24,6 +23,8 @@ import type {
 import { t } from "../../i18n";
 import { renderInteractiveScene } from "../../renderer/interactiveScene";
 
+import { AnimationController } from "../../renderer/animation";
+
 import type {
   AppClassProperties,
   AppState,

packages/excalidraw/components/icons.tsx

@@ -69,6 +69,11 @@ const modifiedTablerIconProps: Opts = {
   strokeLinejoin: "round",
 } as const;
 
+const arrowheadPreviewIconProps: Opts = {
+  width: 40,
+  height: 20,
+} as const;
+
 // -----------------------------------------------------------------------------
 
 // tabler-icons: present
@@ -1291,16 +1296,17 @@ export const ArrowheadNoneIcon = React.memo(
   ({ flip = false }: { flip?: boolean }) =>
     createIcon(
       <g
-        transform={flip ? "translate(24, 0) scale(-1, 1)" : ""}
+        transform={flip ? "translate(40, 0) scale(-1, 1)" : ""}
         stroke="currentColor"
         opacity={0.3}
         strokeWidth={2}
+        fill="none"
+        strokeLinecap="round"
       >
-        <path d="M12 12l-9 0" />
-        <path d="M21 9l-6 6" />
-        <path d="M21 15l-6 -6" />
+        <path d="M7,11 H19" />
+        <path d="M25,6 L33,16 M33,6 L25,16" />
       </g>,
-      tablerIconProps,
+      arrowheadPreviewIconProps,
     ),
 );
 
@@ -1312,57 +1318,12 @@ export const ArrowheadArrowIcon = React.memo(
         stroke="currentColor"
         strokeWidth={2}
         fill="none"
+        strokeLinecap="round"
+        strokeLinejoin="round"
       >
-        <path d="M34 10H6M34 10L27 5M34 10L27 15" />
-        <path d="M27.5 5L34.5 10L27.5 15" />
+        <path d="M7,11 H33 M23,5 L33,11 L23,17" />
       </g>,
-      { width: 40, height: 20 },
-    ),
-);
-
-export const ArrowheadCircleIcon = React.memo(
-  ({ flip = false }: { flip?: boolean }) =>
-    createIcon(
-      <g
-        stroke="currentColor"
-        fill="currentColor"
-        transform={flip ? "translate(40, 0) scale(-1, 1)" : ""}
-      >
-        <path d="M32 10L6 10" strokeWidth={2} />
-        <circle r="4" transform="matrix(-1 0 0 1 30 10)" />
-      </g>,
-      { width: 40, height: 20 },
-    ),
-);
-
-export const ArrowheadCircleOutlineIcon = React.memo(
-  ({ flip = false }: { flip?: boolean }) =>
-    createIcon(
-      <g
-        stroke="currentColor"
-        fill="none"
-        transform={flip ? "translate(40, 0) scale(-1, 1)" : ""}
-        strokeWidth={2}
-      >
-        <path d="M26 10L6 10" />
-        <circle r="4" transform="matrix(-1 0 0 1 30 10)" />
-      </g>,
-      { width: 40, height: 20 },
-    ),
-);
-
-export const ArrowheadBarIcon = React.memo(
-  ({ flip = false }: { flip?: boolean }) =>
-    createIcon(
-      <g transform={flip ? "translate(40, 0) scale(-1, 1)" : ""}>
-        <path
-          d="M34 10H5.99996M34 10L34 5M34 10L34 15"
-          stroke="currentColor"
-          strokeWidth={2}
-          fill="none"
-        />
-      </g>,
-      { width: 40, height: 20 },
+      arrowheadPreviewIconProps,
     ),
 );
 
@@ -1373,11 +1334,12 @@ export const ArrowheadTriangleIcon = React.memo(
         stroke="currentColor"
         fill="currentColor"
         transform={flip ? "translate(40, 0) scale(-1, 1)" : ""}
+        strokeLinejoin="round"
       >
-        <path d="M32 10L6 10" strokeWidth={2} />
-        <path d="M27.5 5.5L34.5 10L27.5 14.5L27.5 5.5" />
+        <path d="M7,11 H23" strokeWidth={2} strokeLinecap="round" />
+        <path d="M23,5 L35,11 L23,17 Z" />
       </g>,
-      { width: 40, height: 20 },
+      arrowheadPreviewIconProps,
     ),
 );
 
@@ -1390,12 +1352,43 @@ export const ArrowheadTriangleOutlineIcon = React.memo(
         transform={flip ? "translate(40, 0) scale(-1, 1)" : ""}
         strokeWidth={2}
         strokeLinejoin="round"
+        strokeLinecap="round"
       >
-        <path d="M6,9.5H27" />
-        <path d="M27,5L34,10L27,14Z" fill="none" />
+        <path d="M7,11 H23" />
+        <path d="M23,5 L35,11 L23,17 Z" />
       </g>,
+      arrowheadPreviewIconProps,
+    ),
+);
 
-      { width: 40, height: 20 },
+export const ArrowheadCircleIcon = React.memo(
+  ({ flip = false }: { flip?: boolean }) =>
+    createIcon(
+      <g
+        stroke="currentColor"
+        fill="currentColor"
+        transform={flip ? "translate(40, 0) scale(-1, 1)" : ""}
+      >
+        <path d="M7,11 H25" strokeWidth={2} strokeLinecap="round" />
+        <circle cx="29" cy="11" r="4" />
+      </g>,
+      arrowheadPreviewIconProps,
+    ),
+);
+
+export const ArrowheadCircleOutlineIcon = React.memo(
+  ({ flip = false }: { flip?: boolean }) =>
+    createIcon(
+      <g
+        stroke="currentColor"
+        fill="none"
+        transform={flip ? "translate(40, 0) scale(-1, 1)" : ""}
+        strokeWidth={2}
+      >
+        <path d="M7,11 H25" strokeLinecap="round" />
+        <circle cx="29" cy="11" r="4" />
+      </g>,
+      arrowheadPreviewIconProps,
     ),
 );
 
@@ -1407,12 +1400,11 @@ export const ArrowheadDiamondIcon = React.memo(
         fill="currentColor"
         transform={flip ? "translate(40, 0) scale(-1, 1)" : ""}
         strokeLinejoin="round"
-        strokeWidth={2}
       >
-        <path d="M6,9.5H20" />
-        <path d="M27,5L34,10L27,14L20,9.5Z" />
+        <path d="M7,11 H21" strokeWidth={2} strokeLinecap="round" />
+        <path d="M21,11 L28,5 L35,11 L28,17 Z" />
       </g>,
-      { width: 40, height: 20 },
+      arrowheadPreviewIconProps,
     ),
 );
 
@@ -1425,15 +1417,32 @@ export const ArrowheadDiamondOutlineIcon = React.memo(
         transform={flip ? "translate(40, 0) scale(-1, 1)" : ""}
         strokeLinejoin="round"
         strokeWidth={2}
+        strokeLinecap="round"
       >
-        <path d="M6,9.5H20" />
-        <path d="M27,5L34,10L27,14L20,9.5Z" />
+        <path d="M7,11 H21" />
+        <path d="M21,11 L28,5 L35,11 L28,17 Z" />
       </g>,
-      { width: 40, height: 20 },
+      arrowheadPreviewIconProps,
     ),
 );
 
-export const ArrowheadCrowfootIcon = React.memo(
+export const ArrowheadBarIcon = React.memo(
+  ({ flip = false }: { flip?: boolean }) =>
+    createIcon(
+      <g
+        transform={flip ? "translate(40, 0) scale(-1, 1)" : ""}
+        stroke="currentColor"
+        strokeWidth={2}
+        fill="none"
+        strokeLinecap="round"
+      >
+        <path d="M11,11 H31 M31,5 V17" />
+      </g>,
+      arrowheadPreviewIconProps,
+    ),
+);
+
+export const ArrowheadCardinalityOneIcon = React.memo(
   ({ flip = false }: { flip?: boolean }) =>
     createIcon(
       <g
@@ -1443,13 +1452,13 @@ export const ArrowheadCrowfootIcon = React.memo(
         strokeLinejoin="round"
         strokeWidth={2}
       >
-        <path d="M34,10 H6 M15,10 L7,5 M15,10 L7,15" />
+        <path d="M35,11 H7 M15,5 V17" />
       </g>,
-      { width: 40, height: 20 },
+      arrowheadPreviewIconProps,
     ),
 );
 
-export const ArrowheadCrowfootOneIcon = React.memo(
+export const ArrowheadCardinalityManyIcon = React.memo(
   ({ flip = false }: { flip?: boolean }) =>
     createIcon(
       <g
@@ -1459,13 +1468,13 @@ export const ArrowheadCrowfootOneIcon = React.memo(
         strokeLinejoin="round"
         strokeWidth={2}
       >
-        <path d="M34,10 H6 M15,10 L15,15 L15,5" />
+        <path d="M35,11 H7 M15,11 L7,5 M15,11 L7,17" />
       </g>,
-      { width: 40, height: 20 },
+      arrowheadPreviewIconProps,
     ),
 );
 
-export const ArrowheadCrowfootOneOrManyIcon = React.memo(
+export const ArrowheadCardinalityOneOrManyIcon = React.memo(
   ({ flip = false }: { flip?: boolean }) =>
     createIcon(
       <g
@@ -1475,9 +1484,59 @@ export const ArrowheadCrowfootOneOrManyIcon = React.memo(
         strokeLinejoin="round"
         strokeWidth={2}
       >
-        <path d="M34,10 H6 M15,10 L15,16 L15,4 M15,10 L7,5 M15,10 L7,15" />
+        <path d="M35,11 H7 M23,5 V17 M15,11 L7,5 M15,11 L7,17" />
       </g>,
-      { width: 40, height: 20 },
+      arrowheadPreviewIconProps,
+    ),
+);
+
+export const ArrowheadCardinalityExactlyOneIcon = React.memo(
+  ({ flip = false }: { flip?: boolean }) =>
+    createIcon(
+      <g
+        stroke="currentColor"
+        fill="none"
+        transform={flip ? "" : "translate(40, 0) scale(-1, 1)"}
+        strokeLinejoin="round"
+        strokeWidth={2}
+      >
+        <path d="M35,11 H7 M15,5 V17 M7,5 V17" />
+      </g>,
+      arrowheadPreviewIconProps,
+    ),
+);
+
+export const ArrowheadCardinalityZeroOrOneIcon = React.memo(
+  ({ flip = false }: { flip?: boolean }) =>
+    createIcon(
+      <g
+        stroke="currentColor"
+        fill="none"
+        transform={flip ? "" : "translate(40, 0) scale(-1, 1)"}
+        strokeLinejoin="round"
+        strokeWidth={2}
+      >
+        <path d="M35,11 H19 M11,11 H7 M7,5 V17" />
+        <circle cx="15" cy="11" r="4" />
+      </g>,
+      arrowheadPreviewIconProps,
+    ),
+);
+
+export const ArrowheadCardinalityZeroOrManyIcon = React.memo(
+  ({ flip = false }: { flip?: boolean }) =>
+    createIcon(
+      <g
+        stroke="currentColor"
+        fill="none"
+        transform={flip ? "" : "translate(40, 0) scale(-1, 1)"}
+        strokeLinejoin="round"
+        strokeWidth={2}
+      >
+        <path d="M35,11 H27 M19,11 H7 M15,11 L7,5 M15,11 L7,17" />
+        <circle cx="23" cy="11" r="4" />
+      </g>,
+      arrowheadPreviewIconProps,
     ),
 );
 

packages/excalidraw/components/main-menu/DefaultItems.tsx

@@ -469,7 +469,6 @@ const PreferencesToggleMidpointSnappingItem = () => {
   return (
     <DropdownMenuItemCheckbox
       checked={appState.isMidpointSnappingEnabled}
-      disabled={appState.bindingPreference === "disabled"}
       onSelect={(event) => {
         actionManager.executeAction(actionToggleMidpointSnapping);
         event.preventDefault();

packages/excalidraw/css/styles.scss

@@ -500,6 +500,26 @@ body.excalidraw-cursor-resize * {
     }
   }
 
+  .floating-status-stack {
+    position: absolute;
+    left: 50%;
+    bottom: 30px;
+    transform: translateX(-50%);
+    display: flex;
+    flex-direction: column;
+    align-items: center;
+    gap: 0.5rem;
+    pointer-events: none;
+
+    .scroll-back-to-content {
+      position: static;
+      left: auto;
+      bottom: auto;
+      transform: none;
+      pointer-events: var(--ui-pointerEvents);
+    }
+  }
+
   .help-icon {
     @include outlineButtonStyles;
     @include filledButtonOnCanvas;

packages/excalidraw/css/theme.scss

@@ -34,9 +34,10 @@
   --popup-text-color: #000;
   --popup-text-inverted-color: #fff;
   --select-highlight-color: #{$color-blue-5};
-  --shadow-island: 0px 0px 0.9310142993927002px 0px rgba(0, 0, 0, 0.17),
-    0px 0px 3.1270833015441895px 0px rgba(0, 0, 0, 0.08),
-    0px 7px 14px 0px rgba(0, 0, 0, 0.05);
+  --shadow-island: 0px 0px 1px 0px rgba(0, 0, 0, 0.17),
+    0px 0px 3px 0px rgba(0, 0, 0, 0.08), 0px 7px 14px 0px rgba(0, 0, 0, 0.05);
+  --shadow-island-stronger: 0px 0px 1px 0px rgba(0, 0, 0, 0.17),
+    0px 0px 3px 0px rgba(0, 0, 0, 0.08), 0px 7px 14px 0px rgb(0 0 0 / 18%);
 
   --button-hover-bg: var(--color-surface-high);
   --button-active-bg: var(--color-surface-high);
@@ -210,9 +211,6 @@
     --popup-text-color: #{$color-gray-4};
     --popup-text-inverted-color: #2c2c2c;
     --select-highlight-color: #{$color-blue-4};
-    --shadow-island: 0px 0px 0.9310142993927002px 0px rgba(0, 0, 0, 0.17),
-      0px 0px 3.1270833015441895px 0px rgba(0, 0, 0, 0.08),
-      0px 7px 14px 0px rgba(0, 0, 0, 0.05);
 
     --modal-shadow: 0px 100px 80px rgba(0, 0, 0, 0.07),
       0px 41.7776px 33.4221px rgba(0, 0, 0, 0.0503198),

packages/excalidraw/data/blob.ts

@@ -27,7 +27,6 @@ import {
 
 import type { AppState, DataURL, LibraryItem } from "../types";
 
-import type { FileSystemHandle } from "browser-fs-access";
 import type { ImportedLibraryData } from "./types";
 
 const parseFileContents = async (blob: Blob | File): Promise<string> => {
@@ -104,7 +103,7 @@ export const getMimeType = (blob: Blob | string): string => {
   return "";
 };
 
-export const getFileHandleType = (handle: FileSystemHandle | null) => {
+export const getFileHandleType = (handle: FileSystemFileHandle | null) => {
   if (!handle) {
     return null;
   }
@@ -118,7 +117,9 @@ export const isImageFileHandleType = (
   return type === "png" || type === "svg";
 };
 
-export const isImageFileHandle = (handle: FileSystemHandle | null) => {
+export const isImageFileHandle = (
+  handle: FileSystemFileHandle | null,
+): handle is FileSystemFileHandle => {
   const type = getFileHandleType(handle);
   return type === "png" || type === "svg";
 };
@@ -139,8 +140,8 @@ export const loadSceneOrLibraryFromBlob = async (
   /** @see restore.localAppState */
   localAppState: AppState | null,
   localElements: readonly ExcalidrawElement[] | null,
-  /** FileSystemHandle. Defaults to `blob.handle` if defined, otherwise null. */
-  fileHandle?: FileSystemHandle | null,
+  /** FileSystemFileHandle. Defaults to `blob.handle` if defined, otherwise null. */
+  fileHandle?: FileSystemFileHandle | null,
 ) => {
   const contents = await parseFileContents(blob);
   let data;
@@ -198,8 +199,8 @@ export const loadFromBlob = async (
   /** @see restore.localAppState */
   localAppState: AppState | null,
   localElements: readonly ExcalidrawElement[] | null,
-  /** FileSystemHandle. Defaults to `blob.handle` if defined, otherwise null. */
-  fileHandle?: FileSystemHandle | null,
+  /** FileSystemFileHandle. Defaults to `blob.handle` if defined, otherwise null. */
+  fileHandle?: FileSystemFileHandle | null,
 ) => {
   const ret = await loadSceneOrLibraryFromBlob(
     blob,
@@ -392,7 +393,7 @@ export const ImageURLToFile = async (
 
 export const getFileHandle = async (
   event: DragEvent | React.DragEvent | DataTransferItem,
-): Promise<FileSystemHandle | null> => {
+): Promise<FileSystemFileHandle | null> => {
   if (nativeFileSystemSupported) {
     try {
       const dataTransferItem =
@@ -400,7 +401,7 @@ export const getFileHandle = async (
           ? event
           : (event as DragEvent).dataTransfer?.items?.[0];
 
-      const handle: FileSystemHandle | null =
+      const handle: FileSystemFileHandle | null =
         (await (dataTransferItem as any).getAsFileSystemHandle()) || null;
 
       return handle;

packages/excalidraw/data/filesystem.ts

@@ -4,18 +4,12 @@ import {
   supported as nativeFileSystemSupported,
 } from "browser-fs-access";
 
-import { EVENT, MIME_TYPES, debounce } from "@excalidraw/common";
-
-import { AbortError } from "../errors";
+import { MIME_TYPES } from "@excalidraw/common";
 
 import { normalizeFile } from "./blob";
 
-import type { FileSystemHandle } from "browser-fs-access";
-
 type FILE_EXTENSION = Exclude<keyof typeof MIME_TYPES, "binary">;
 
-const INPUT_CHANGE_INTERVAL_MS = 5000;
-
 export const fileOpen = async <M extends boolean | undefined = false>(opts: {
   extensions?: FILE_EXTENSION[];
   description: string;
@@ -42,40 +36,6 @@ export const fileOpen = async <M extends boolean | undefined = false>(opts: {
     extensions,
     mimeTypes,
     multiple: opts.multiple ?? false,
-    legacySetup: (resolve, reject, input) => {
-      const scheduleRejection = debounce(reject, INPUT_CHANGE_INTERVAL_MS);
-      const focusHandler = () => {
-        checkForFile();
-        document.addEventListener(EVENT.KEYUP, scheduleRejection);
-        document.addEventListener(EVENT.POINTER_UP, scheduleRejection);
-        scheduleRejection();
-      };
-      const checkForFile = () => {
-        // this hack might not work when expecting multiple files
-        if (input.files?.length) {
-          const ret = opts.multiple ? [...input.files] : input.files[0];
-          resolve(ret as RetType);
-        }
-      };
-      requestAnimationFrame(() => {
-        window.addEventListener(EVENT.FOCUS, focusHandler);
-      });
-      const interval = window.setInterval(() => {
-        checkForFile();
-      }, INPUT_CHANGE_INTERVAL_MS);
-      return (rejectPromise) => {
-        clearInterval(interval);
-        scheduleRejection.cancel();
-        window.removeEventListener(EVENT.FOCUS, focusHandler);
-        document.removeEventListener(EVENT.KEYUP, scheduleRejection);
-        document.removeEventListener(EVENT.POINTER_UP, scheduleRejection);
-        if (rejectPromise) {
-          // so that something is shown in console if we need to debug this
-          console.warn("Opening the file was canceled (legacy-fs).");
-          rejectPromise(new AbortError());
-        }
-      };
-    },
   });
 
   if (Array.isArray(files)) {
@@ -95,8 +55,8 @@ export const fileSave = (
     extension: FILE_EXTENSION;
     mimeTypes?: string[];
     description: string;
-    /** existing FileSystemHandle */
-    fileHandle?: FileSystemHandle | null;
+    /** existing FileSystemFileHandle */
+    fileHandle?: FileSystemFileHandle | null;
   },
 ) => {
   return _fileSave(
@@ -108,8 +68,8 @@ export const fileSave = (
       mimeTypes: opts.mimeTypes,
     },
     opts.fileHandle,
+    false,
   );
 };
 
 export { nativeFileSystemSupported };
-export type { FileSystemHandle };

packages/excalidraw/data/index.ts

@@ -33,8 +33,6 @@ import { canvasToBlob } from "./blob";
 import { fileSave } from "./filesystem";
 import { serializeAsJSON } from "./json";
 
-import type { FileSystemHandle } from "./filesystem";
-
 import type { ExportType } from "../scene/types";
 import type { AppState, BinaryFiles } from "../types";
 
@@ -110,7 +108,7 @@ export const exportCanvas = async (
     viewBackgroundColor: string;
     /** filename, if applicable */
     name?: string;
-    fileHandle?: FileSystemHandle | null;
+    fileHandle?: FileSystemFileHandle | null;
     exportingFrame: ExcalidrawFrameLikeElement | null;
   },
 ) => {

packages/excalidraw/data/json.ts

@@ -1,12 +1,13 @@
 import {
-  DEFAULT_FILENAME,
   EXPORT_DATA_TYPES,
   getExportSource,
   MIME_TYPES,
   VERSIONS,
 } from "@excalidraw/common";
 
-import type { ExcalidrawElement } from "@excalidraw/element/types";
+import type { ExcalidrawElement, NonDeleted } from "@excalidraw/element/types";
+
+import type { MaybePromise } from "@excalidraw/common/utility-types";
 
 import { cleanAppStateForExport, clearAppStateForDatabase } from "../appState";
 
@@ -21,6 +22,12 @@ import type {
   ImportedLibraryData,
 } from "./types";
 
+export type JSONExportData = {
+  elements: readonly NonDeleted<ExcalidrawElement>[];
+  appState: AppState;
+  files: BinaryFiles;
+};
+
 /**
  * Strips out files which are only referenced by deleted elements
  */
@@ -67,27 +74,29 @@ export const serializeAsJSON = (
   return JSON.stringify(data, null, 2);
 };
 
-export const saveAsJSON = async (
-  elements: readonly ExcalidrawElement[],
-  appState: AppState,
-  files: BinaryFiles,
-  /** filename */
-  name: string = appState.name || DEFAULT_FILENAME,
-) => {
-  const serialized = serializeAsJSON(elements, appState, files, "local");
-  const blob = new Blob([serialized], {
-    type: MIME_TYPES.excalidraw,
+export const saveAsJSON = async ({
+  data,
+  filename,
+  fileHandle,
+}: {
+  data: MaybePromise<JSONExportData>;
+  filename: string;
+  fileHandle: AppState["fileHandle"];
+}) => {
+  const blob = Promise.resolve(data).then(({ elements, appState, files }) => {
+    const serialized = serializeAsJSON(elements, appState, files, "local");
+    return new Blob([serialized], {
+      type: MIME_TYPES.excalidraw,
+    });
   });
 
-  const fileHandle = await fileSave(blob, {
-    name,
+  const savedFileHandle = await fileSave(blob, {
+    name: filename,
     extension: "excalidraw",
     description: "Excalidraw file",
-    fileHandle: isImageFileHandle(appState.fileHandle)
-      ? null
-      : appState.fileHandle,
+    fileHandle: isImageFileHandle(fileHandle) ? null : fileHandle,
   });
-  return { fileHandle };
+  return { fileHandle: savedFileHandle };
 };
 
 export const loadFromJSON = async (

packages/excalidraw/data/resave.ts

@@ -1,26 +1,35 @@
+import type { MaybePromise } from "@excalidraw/common/utility-types";
+
 import type { ExcalidrawElement } from "@excalidraw/element/types";
 
 import { getFileHandleType, isImageFileHandleType } from "./blob";
 
+// eslint-disable-next-line @typescript-eslint/no-restricted-imports
 import { exportCanvas, prepareElementsForExport } from ".";
 
 import type { AppState, BinaryFiles } from "../types";
 
 export const resaveAsImageWithScene = async (
-  elements: readonly ExcalidrawElement[],
-  appState: AppState,
-  files: BinaryFiles,
-  name: string,
+  data: MaybePromise<{
+    elements: readonly ExcalidrawElement[];
+    appState: AppState;
+    files: BinaryFiles;
+  }>,
+  fileHandle: FileSystemFileHandle,
+  filename: string,
 ) => {
-  const { exportBackground, viewBackgroundColor, fileHandle } = appState;
-
   const fileHandleType = getFileHandleType(fileHandle);
 
-  if (!fileHandle || !isImageFileHandleType(fileHandleType)) {
+  if (!isImageFileHandleType(fileHandleType)) {
     throw new Error(
       "fileHandle should exist and should be of type svg or png when resaving",
     );
   }
+
+  let { elements, appState, files } = await data;
+
+  const { exportBackground, viewBackgroundColor } = appState;
+
   appState = {
     ...appState,
     exportEmbedScene: true,
@@ -35,7 +44,7 @@ export const resaveAsImageWithScene = async (
   await exportCanvas(fileHandleType, exportedElements, appState, files, {
     exportBackground,
     viewBackgroundColor,
-    name,
+    name: filename,
     fileHandle,
     exportingFrame,
   });

packages/excalidraw/data/restore.ts

@@ -22,6 +22,7 @@ import {
 import {
   calculateFixedPointForNonElbowArrowBinding,
   getNonDeletedElements,
+  normalizeArrowhead,
   isPointInElement,
   isValidPolygon,
   projectFixedPointOntoDiagonal,
@@ -426,7 +427,8 @@ export const restoreElement = (
     // @ts-ignore LEGACY type
     // eslint-disable-next-line no-fallthrough
     case "draw":
-      const { startArrowhead = null, endArrowhead = null } = element;
+      const startArrowhead = normalizeArrowhead(element.startArrowhead);
+      const endArrowhead = normalizeArrowhead(element.endArrowhead);
       let x = element.x;
       let y = element.y;
       let points = // migrate old arrow model to new one
@@ -458,7 +460,11 @@ export const restoreElement = (
         ...getSizeFromPoints(points),
       });
     case "arrow": {
-      const { startArrowhead = null, endArrowhead = "arrow" } = element;
+      const startArrowhead = normalizeArrowhead(element.startArrowhead);
+      const endArrowhead =
+        element.endArrowhead === undefined
+          ? "arrow"
+          : normalizeArrowhead(element.endArrowhead);
       const x: number | undefined = element.x;
       const y: number | undefined = element.y;
       const points: readonly LocalPoint[] | undefined = // migrate old arrow model to new one

packages/excalidraw/global.d.ts

@@ -52,7 +52,7 @@ declare module "png-chunks-extract" {
 // -----------------------------------------------------------------------------
 
 interface Blob {
-  handle?: import("browser-fs-acces").FileSystemHandle;
+  handle?: FileSystemFileHandle;
   name?: string;
 }
 

packages/excalidraw/hooks/useAppStateValue.ts

@@ -0,0 +1,172 @@
+import { useEffect, useRef, useState } from "react";
+
+import { useExcalidrawAPI } from "../components/App";
+
+import { getDefaultAppState } from "../appState";
+
+import type { AppState } from "../types";
+
+type AppStateSelector =
+  | keyof AppState
+  | (keyof AppState)[]
+  | ((appState: AppState) => unknown);
+
+const getSelectedValue = (appState: AppState, selector: AppStateSelector) => {
+  if (typeof selector === "function") {
+    return selector(appState);
+  }
+  if (Array.isArray(selector)) {
+    return appState;
+  }
+  return appState[selector];
+};
+
+const getLatestValue = (
+  api: ReturnType<typeof useExcalidrawAPI>,
+  selector: AppStateSelector,
+  _internal: boolean,
+) => {
+  if (api?.isDestroyed) {
+    return;
+  }
+
+  let appState = api?.getAppState();
+  if (!appState) {
+    if (!_internal) {
+      return undefined;
+    }
+
+    console.warn(
+      "useAppStateValue: excalidrawAPI not defined yet for internal component while it should always be defined. Are you sure you're rendering inside of <Excalidraw/> component tree?",
+    );
+    // fall back in case there's a bug so we don't break the app
+    // (internal components using this internal useAppStateValue expect
+    //  non-undefined values on init)
+    appState = Object.assign(
+      { width: 0, height: 0, offsetLeft: 0, offsetTop: 0 },
+      getDefaultAppState(),
+    );
+  }
+
+  return getSelectedValue(appState, selector);
+};
+
+/**
+ * Subscribes to specific appState changes. The component re-renders
+ * only when the specified prop(s) change — not on every appState update.
+ *
+ * Works both inside and outside the <Excalidraw> tree, as long as
+ * ExcalidrawAPIContext.Provider is an ancestor (automatically provided
+ * inside <Excalidraw>, or manually by the host app).
+ *
+ * Returns the narrowed value depending on prop form:
+ *  - `keyof AppState` → `AppState[K]`
+ *  - `(keyof AppState)[]` → whole `AppState`
+ *  - selector function → selector's return type `T`
+ *
+ * If excalidrawAPI is not ready yet (host apps), hook is rerendered with latest
+ * value once available.
+ */
+export function useAppStateValue<K extends keyof AppState>(
+  prop: K,
+  _internal?: boolean,
+): AppState[K];
+export function useAppStateValue(
+  props: (keyof AppState)[],
+  _internal?: boolean,
+): AppState;
+export function useAppStateValue<T>(
+  selector: (appState: AppState) => T,
+  _internal?: boolean,
+): T;
+export function useAppStateValue(
+  selector: AppStateSelector,
+  _internal: boolean = true,
+): unknown {
+  const api = useExcalidrawAPI();
+  const [, rerender] = useState(0);
+
+  const stateRef = useRef<{
+    selector: AppStateSelector;
+    isInitialized: boolean;
+    latestValue: unknown;
+  } | null>(null);
+  if (!stateRef.current) {
+    stateRef.current = {
+      selector,
+      isInitialized: !!api,
+      latestValue: getLatestValue(api, selector, _internal),
+    };
+  }
+  stateRef.current.selector = selector;
+  if (!stateRef.current.isInitialized && api && !api.isDestroyed) {
+    stateRef.current.isInitialized = true;
+    stateRef.current.latestValue = getLatestValue(api, selector, _internal);
+  }
+
+  useEffect(() => {
+    const currentStateRef = stateRef.current;
+    if (!api || api.isDestroyed || !currentStateRef) {
+      return;
+    }
+
+    return api.onStateChange(currentStateRef.selector, (newValue: any) => {
+      currentStateRef.latestValue = newValue;
+      rerender((value) => value + 1);
+    });
+  }, [api]);
+
+  return stateRef.current.latestValue;
+}
+
+/**
+ * Subscribes to specific appState changes without causing component rerenders.
+ *
+ * The callback is called on every matching change, but also on initial render
+ * so you can initialize your state.
+ */
+export function useOnAppStateChange<K extends keyof AppState>(
+  prop: K,
+  callback: (value: AppState[K], appState: AppState) => void,
+): undefined;
+export function useOnAppStateChange(
+  props: (keyof AppState)[],
+  callback: (props: AppState, appState: AppState) => void,
+): undefined;
+export function useOnAppStateChange<T>(
+  selector: (appState: AppState) => T,
+  callback: (value: T, appState: AppState) => void,
+): undefined;
+export function useOnAppStateChange(
+  selector: AppStateSelector,
+  callback: (value: any, appState: AppState) => void,
+): undefined {
+  const api = useExcalidrawAPI();
+
+  const stateRef = useRef({
+    selector,
+    callback,
+  });
+  stateRef.current.selector = selector;
+  stateRef.current.callback = callback;
+
+  useEffect(() => {
+    if (!api || api.isDestroyed) {
+      return;
+    }
+
+    stateRef.current.callback(
+      getLatestValue(api, stateRef.current.selector, true),
+      api.getAppState(),
+    );
+
+    return api.onStateChange(
+      stateRef.current.selector,
+      (newValue: any, state: AppState) => {
+        stateRef.current.callback(newValue, state);
+      },
+    );
+  }, [api]);
+
+  return undefined;
+}

packages/excalidraw/index.tsx

@@ -1,14 +1,27 @@
-import React, { useEffect } from "react";
+import React, {
+  useCallback,
+  useContext,
+  useEffect,
+  useRef,
+  useState,
+} from "react";
 
 import { DEFAULT_UI_OPTIONS, isShallowEqual } from "@excalidraw/common";
 
-import App from "./components/App";
+import App, {
+  ExcalidrawAPIContext,
+  ExcalidrawAPISetContext,
+} from "./components/App";
 import { InitializeApp } from "./components/InitializeApp";
 import Footer from "./components/footer/FooterCenter";
 import LiveCollaborationTrigger from "./components/live-collaboration/LiveCollaborationTrigger";
 import MainMenu from "./components/main-menu/MainMenu";
 import WelcomeScreen from "./components/welcome-screen/WelcomeScreen";
 import { defaultLang } from "./i18n";
+import {
+  useAppStateValue as _useAppStateValue,
+  useOnAppStateChange as _useOnAppStateChange,
+} from "./hooks/useAppStateValue";
 import { EditorJotaiProvider, editorJotaiStore } from "./editor-jotai";
 import polyfill from "./polyfill";
 
@@ -16,16 +29,45 @@ import "./css/app.scss";
 import "./css/styles.scss";
 import "./fonts/fonts.css";
 
-import type { AppProps, ExcalidrawProps } from "./types";
+import type {
+  AppProps,
+  AppState,
+  ExcalidrawImperativeAPI,
+  ExcalidrawProps,
+} from "./types";
 
 polyfill();
 
+/**
+ * Stateless provider that allows `useExcalidrawAPI()` (and hooks built
+ * on it, such as `useAppStateValue()` and `useOnAppStateChange()`) to work
+ * outside the <Excalidraw> component tree.
+ */
+export const ExcalidrawAPIProvider = ({
+  children,
+}: {
+  children: React.ReactNode;
+}) => {
+  const [api, setApi] = useState<ExcalidrawImperativeAPI | null>(null);
+  return (
+    <ExcalidrawAPIContext.Provider value={api}>
+      <ExcalidrawAPISetContext.Provider value={setApi}>
+        {children}
+      </ExcalidrawAPISetContext.Provider>
+    </ExcalidrawAPIContext.Provider>
+  );
+};
+
 const ExcalidrawBase = (props: ExcalidrawProps) => {
   const {
+    onExport,
     onChange,
     onIncrement,
     initialData,
-    excalidrawAPI,
+    onExcalidrawAPI,
+    onMount,
+    onUnmount,
+    onInitialize,
     isCollaborating = false,
     onPointerUpdate,
     renderTopLeftUI,
@@ -86,6 +128,19 @@ const ExcalidrawBase = (props: ExcalidrawProps) => {
     UIOptions.canvasActions.toggleTheme = true;
   }
 
+  const setExcalidrawAPI = useContext(ExcalidrawAPISetContext);
+
+  const onExcalidrawAPIRef = useRef(onExcalidrawAPI);
+  onExcalidrawAPIRef.current = onExcalidrawAPI;
+
+  const handleExcalidrawAPI = useCallback(
+    (api: ExcalidrawImperativeAPI | null) => {
+      setExcalidrawAPI?.(api);
+      onExcalidrawAPIRef.current?.(api);
+    },
+    [setExcalidrawAPI],
+  );
+
   useEffect(() => {
     const importPolyfill = async () => {
       //@ts-ignore
@@ -115,10 +170,14 @@ const ExcalidrawBase = (props: ExcalidrawProps) => {
     <EditorJotaiProvider store={editorJotaiStore}>
       <InitializeApp langCode={langCode} theme={theme}>
         <App
+          onExport={onExport}
           onChange={onChange}
           onIncrement={onIncrement}
           initialData={initialData}
-          excalidrawAPI={excalidrawAPI}
+          onExcalidrawAPI={handleExcalidrawAPI}
+          onMount={onMount}
+          onUnmount={onUnmount}
+          onInitialize={onInitialize}
           isCollaborating={isCollaborating}
           onPointerUpdate={onPointerUpdate}
           renderTopLeftUI={renderTopLeftUI}
@@ -267,6 +326,7 @@ export {
   sceneCoordsToViewportCoords,
   viewportCoordsToSceneCoords,
   getFormFactor,
+  throttleRAF,
 } from "@excalidraw/common";
 
 export {
@@ -284,7 +344,13 @@ export { Button } from "./components/Button";
 export { Footer };
 export { MainMenu };
 export { Ellipsify } from "./components/Ellipsify";
-export { useEditorInterface, useStylesPanelMode } from "./components/App";
+export {
+  useEditorInterface,
+  useStylesPanelMode,
+  useExcalidrawAPI,
+  ExcalidrawAPIContext,
+} from "./components/App";
+
 export { WelcomeScreen };
 export { LiveCollaborationTrigger };
 export { Stats } from "./components/Stats";
@@ -325,3 +391,35 @@ export {
   tryParseSpreadsheet,
   isSpreadsheetValidForChartType,
 } from "./charts";
+
+// -----------------------------------------------------------------------------
+// useExcalidrawStateValue() wrapper for host apps for the return type to reflect the
+// the potentially `undefined` value for initial render before the excalidrawAPI
+// is ready.
+//
+/**
+ * hook that subscribes to specific appState prop(s)
+ *
+ * @param prop - appState prop(s) to subscribe to, or a selector function.
+ * NOTE `prop/selector` is memoized and will not change after initial render
+ */
+export function useExcalidrawStateValue<K extends keyof AppState>(
+  prop: K,
+): AppState[K] | undefined;
+export function useExcalidrawStateValue<T extends keyof AppState>(
+  props: T[],
+): AppState | undefined;
+export function useExcalidrawStateValue<T>(
+  selector: (appState: AppState) => T,
+): T | undefined;
+export function useExcalidrawStateValue(
+  selector:
+    | keyof AppState
+    | (keyof AppState)[]
+    | ((appState: AppState) => unknown),
+) {
+  return _useAppStateValue(selector as any, false);
+}
+// -----------------------------------------------------------------------------
+
+export { _useOnAppStateChange as useOnExcalidrawStateChange };

packages/excalidraw/locales/en.json

@@ -53,7 +53,14 @@
     "arrowhead_crowfoot_many": "Crow's foot (many)",
     "arrowhead_crowfoot_one": "Crow's foot (one)",
     "arrowhead_crowfoot_one_or_many": "Crow's foot (one or many)",
+    "arrowhead_cardinality_one": "Cardinality (one)",
+    "arrowhead_cardinality_many": "Cardinality (many)",
+    "arrowhead_cardinality_one_or_many": "Cardinality (one or many)",
+    "arrowhead_cardinality_exactly_one": "Cardinality (exactly one)",
+    "arrowhead_cardinality_zero_or_one": "Cardinality (zero or one)",
+    "arrowhead_cardinality_zero_or_many": "Cardinality (zero or many)",
     "more_options": "More options",
+    "cardinality": "Cardinality",
     "arrowtypes": "Arrow type",
     "arrowtype_sharp": "Sharp arrow",
     "arrowtype_round": "Curved arrow",
@@ -403,6 +410,10 @@
   "errorDialog": {
     "title": "Error"
   },
+  "progressDialog": {
+    "title": "Saving",
+    "defaultMessage": "Preparing to save..."
+  },
   "exportDialog": {
     "disk_title": "Save to disk",
     "disk_details": "Export the scene data to a file from which you can import later.",
@@ -620,11 +631,12 @@
   "mermaid": {
     "title": "Mermaid to Excalidraw",
     "button": "Insert",
-    "description": "Currently only <flowchartLink>Flowchart</flowchartLink>,<sequenceLink> Sequence, </sequenceLink> and <classLink>Class </classLink>Diagrams are supported. The other types will be rendered as image in Excalidraw.",
+    "description": "Currently only <flowchartLink>Flowchart</flowchartLink>, <sequenceLink>Sequence</sequenceLink>, <classLink>Class</classLink>, and <erdLink>Entity Relationship</erdLink> Diagrams are supported. The other types will be rendered as image in Excalidraw.",
     "syntax": "Mermaid Syntax",
     "preview": "Preview",
     "label": "Mermaid",
-    "inputPlaceholder": "Write Mermaid diagram defintion here..."
+    "inputPlaceholder": "Write Mermaid diagram defintion here...",
+    "autoFixAvailable": "Auto-fix is available"
   },
   "ttd": {
     "error": "Error!"
@@ -649,7 +661,7 @@
     "placeholder": {
       "title": "Let's design your diagram",
       "description": "Describe the diagram you want to create, and we'll generate it for you.",
-      "hint": "At the moment we know Flowchart, Sequence, and Class diagrams."
+      "hint": "At the moment we know Flowchart, Sequence, Class, and Entity Relationship diagrams."
     },
     "preview": "Preview",
     "insert": "Insert",

packages/excalidraw/package.json

@@ -79,14 +79,18 @@
   },
   "dependencies": {
     "@braintree/sanitize-url": "6.0.2",
+    "@codemirror/commands": "^6.0.0",
+    "@codemirror/language": "^6.0.0",
+    "@codemirror/state": "^6.0.0",
+    "@codemirror/view": "^6.0.0",
+    "@lezer/highlight": "^1.0.0",
     "@excalidraw/common": "0.18.0",
     "@excalidraw/element": "0.18.0",
     "@excalidraw/laser-pointer": "1.3.1",
     "@excalidraw/math": "0.18.0",
-    "@excalidraw/mermaid-to-excalidraw": "2.0.0-rfc3",
+    "@excalidraw/mermaid-to-excalidraw": "2.1.1",
     "@excalidraw/random-username": "1.1.0",
-    "radix-ui": "1.4.3",
-    "browser-fs-access": "0.29.1",
+    "browser-fs-access": "0.38.0",
     "canvas-roundrect-polyfill": "0.0.1",
     "clsx": "1.1.1",
     "cross-env": "7.0.3",
@@ -107,6 +111,7 @@
     "png-chunks-extract": "1.0.0",
     "points-on-curve": "1.0.1",
     "pwacompat": "2.0.17",
+    "radix-ui": "1.4.3",
     "roughjs": "4.6.4",
     "sass": "1.51.0",
     "tunnel-rat": "0.1.2"

packages/excalidraw/renderer/renderNewElementScene.ts

@@ -88,7 +88,6 @@ export const renderNewElementSceneThrottled = throttleRAF(
   (config: NewElementSceneRenderConfig) => {
     _renderNewElementScene(config);
   },
-  { trailing: true },
 );
 
 export const renderNewElementScene = (

packages/excalidraw/renderer/staticScene.ts

@@ -483,7 +483,6 @@ export const renderStaticSceneThrottled = throttleRAF(
   (config: StaticSceneRenderConfig) => {
     _renderStaticScene(config);
   },
-  { trailing: true },
 );
 
 /**

packages/excalidraw/tests/MermaidToExcalidraw.test.tsx

@@ -1,5 +1,4 @@
-import React from "react";
-import { expect } from "vitest";
+import { expect, vi } from "vitest";
 
 import { Excalidraw } from "../index";
 
@@ -7,6 +6,13 @@ import { mockMermaidToExcalidraw } from "./helpers/mocks";
 import { getTextEditor, updateTextEditor } from "./queries/dom";
 import { render, waitFor } from "./test-utils";
 
+// Mock CodeMirror deps so the dynamic import of CodeMirrorEditor fails,
+// causing TTDDialogInput to fall back to <textarea> in tests.
+vi.mock("@codemirror/view", () => ({}));
+vi.mock("@codemirror/state", () => ({}));
+vi.mock("@codemirror/language", () => ({}));
+vi.mock("@lezer/highlight", () => ({}));
+
 mockMermaidToExcalidraw({
   mockRef: true,
   parseMermaidToExcalidraw: async (definition) => {

packages/excalidraw/tests/__snapshots__/MermaidToExcalidraw.test.tsx.snap

@@ -1,13 +1,6 @@
 // Vitest Snapshot v1, https://vitest.dev/guide/snapshot.html
 
-exports[`Test <MermaidToExcalidraw/> > should open mermaid popup when active tool is mermaid 1`] = `
-"<div class="Modal Dialog ttd-dialog" role="dialog" aria-modal="true" aria-labelledby="dialog-title"><div class="Modal__background"></div><div class="Modal__content" style="--max-width: 1520px;" tabindex="0"><div class="Island"><div class="Dialog__content"><div dir="ltr" data-orientation="horizontal" class="ttd-dialog-tabs-root"><p class="dialog-mermaid-title">Mermaid to Excalidraw</p><div data-state="active" data-orientation="horizontal" role="tabpanel" aria-labelledby="radix-:r4:-trigger-mermaid" id="radix-:r4:-content-mermaid" tabindex="0" class="ttd-dialog-content" style=""><div class="ttd-dialog-desc">Currently only <a href="https://mermaid.js.org/syntax/flowchart.html">Flowchart</a>,<a href="https://mermaid.js.org/syntax/sequenceDiagram.html"> Sequence, </a> and <a href="https://mermaid.js.org/syntax/classDiagram.html">Class </a>Diagrams are supported. The other types will be rendered as image in Excalidraw.</div><div class="ttd-dialog-panels"><div class="ttd-dialog-panel"><textarea class="ttd-dialog-input" placeholder="Write Mermaid diagram defintion here...">flowchart TD
- A[Christmas] --&gt;|Get money| B(Go shopping)
- B --&gt; C{Let me think}
- C --&gt;|One| D[Laptop]
- C --&gt;|Two| E[iPhone]
- C --&gt;|Three| F[Car]</textarea><div class="ttd-dialog-panel-button-container invisible" style="justify-content: flex-start;"></div></div><div class="ttd-dialog-panel"><div class="ttd-dialog-output-wrapper "><div class="ttd-dialog-output-canvas-container"><div class="ttd-dialog-output-canvas-content"><canvas width="89" height="158" dir="ltr"></canvas></div></div></div><div class="ttd-dialog-panel-button-container" style="justify-content: flex-start;"><button type="button" class="excalidraw-button ttd-dialog-panel-button"><div class="">Insert<span><svg aria-hidden="true" focusable="false" role="img" viewBox="0 0 20 20" class="" fill="none" stroke="currentColor" stroke-linecap="round" stroke-linejoin="round"><g stroke-width="1.25"><path d="M4.16602 10H15.8327"></path><path d="M12.5 13.3333L15.8333 10"></path><path d="M12.5 6.66666L15.8333 9.99999"></path></g></svg></span></div></button><div class="ttd-dialog-submit-shortcut"><div class="ttd-dialog-submit-shortcut__key">Ctrl</div><div class="ttd-dialog-submit-shortcut__key">Enter</div></div></div></div></div></div></div></div></div></div></div>"
-`;
+exports[`Test <MermaidToExcalidraw/> > should open mermaid popup when active tool is mermaid 1`] = `"<div class="Modal Dialog ttd-dialog" role="dialog" aria-modal="true" aria-labelledby="dialog-title"><div class="Modal__background"></div><div class="Modal__content" style="--max-width: 1520px;" tabindex="0"><div class="Island"><div class="Dialog__content"><div dir="ltr" data-orientation="horizontal" class="ttd-dialog-tabs-root"><p class="dialog-mermaid-title">Mermaid to Excalidraw</p><div data-state="active" data-orientation="horizontal" role="tabpanel" aria-labelledby="radix-:r4:-trigger-mermaid" id="radix-:r4:-content-mermaid" tabindex="0" class="ttd-dialog-content" style=""><div class="ttd-dialog-desc">Currently only <a href="https://mermaid.js.org/syntax/flowchart.html" target="_blank" rel="noreferrer">Flowchart</a>, <a href="https://mermaid.js.org/syntax/sequenceDiagram.html" target="_blank" rel="noreferrer">Sequence</a>, <a href="https://mermaid.js.org/syntax/classDiagram.html" target="_blank" rel="noreferrer">Class</a>, and <a href="https://mermaid.js.org/syntax/entityRelationshipDiagram.html" target="_blank" rel="noreferrer">Entity Relationship</a> Diagrams are supported. The other types will be rendered as image in Excalidraw.</div><div class="ttd-dialog-panels"><div class="ttd-dialog-panel"><div class="ttd-dialog-panel-button-container invisible" style="justify-content: flex-start;"></div></div><div class="ttd-dialog-panel"><div class="ttd-dialog-output-wrapper "><div class="ttd-dialog-output-canvas-container"><div class="ttd-dialog-output-canvas-content"><canvas width="89" height="158" dir="ltr"></canvas></div></div></div><div class="ttd-dialog-panel-button-container" style="justify-content: flex-start;"><button type="button" class="excalidraw-button ttd-dialog-panel-button"><div class="">Insert<span><svg aria-hidden="true" focusable="false" role="img" viewBox="0 0 20 20" class="" fill="none" stroke="currentColor" stroke-linecap="round" stroke-linejoin="round"><g stroke-width="1.25"><path d="M4.16602 10H15.8327"></path><path d="M12.5 13.3333L15.8333 10"></path><path d="M12.5 6.66666L15.8333 9.99999"></path></g></svg></span></div></button><div class="ttd-dialog-submit-shortcut"><div class="ttd-dialog-submit-shortcut__key">Ctrl</div><div class="ttd-dialog-submit-shortcut__key">Enter</div></div></div></div></div></div></div></div></div></div></div>"`;
 
 exports[`Test <MermaidToExcalidraw/> > should show error in preview when mermaid library throws error 1`] = `
 "flowchart TD

packages/excalidraw/tests/__snapshots__/excalidraw.test.tsx.snap

@@ -2,7 +2,7 @@
 
 exports[`<Excalidraw/> > <MainMenu/> > should render main menu with host menu items if passed from host 1`] = `
 <div
-  aria-labelledby="radix-:r7t:"
+  aria-labelledby="radix-:r85:"
   aria-orientation="vertical"
   class="dropdown-menu main-menu"
   data-align="start"
@@ -12,7 +12,7 @@ exports[`<Excalidraw/> > <MainMenu/> > should render main menu with host menu it
   data-state="open"
   data-testid="dropdown-menu"
   dir="ltr"
-  id="radix-:r7u:"
+  id="radix-:r86:"
   role="menu"
   style="outline: none; --radix-dropdown-menu-content-transform-origin: var(--radix-popper-transform-origin); --radix-dropdown-menu-content-available-width: var(--radix-popper-available-width); --radix-dropdown-menu-content-available-height: var(--radix-popper-available-height); --radix-dropdown-menu-trigger-width: var(--radix-popper-anchor-width); --radix-dropdown-menu-trigger-height: var(--radix-popper-anchor-height); animation: none;"
   tabindex="-1"

packages/excalidraw/tests/appStateHooks.test.tsx

@@ -0,0 +1,111 @@
+import { act, cleanup, render, screen } from "@testing-library/react";
+import { vi } from "vitest";
+
+import { getDefaultAppState } from "../appState";
+import { ExcalidrawAPIContext } from "../components/App";
+import { AppStateObserver } from "../components/AppStateObserver";
+import {
+  useAppStateValue,
+  useOnAppStateChange,
+} from "../hooks/useAppStateValue";
+
+import type { AppState, ExcalidrawImperativeAPI } from "../types";
+
+const createAppState = (): AppState => ({
+  ...getDefaultAppState(),
+  width: 0,
+  height: 0,
+  offsetLeft: 0,
+  offsetTop: 0,
+});
+
+const createMockAPI = (initialState: AppState) => {
+  let state = initialState;
+  const observer = new AppStateObserver(() => state);
+
+  return {
+    api: {
+      isDestroyed: false,
+      getAppState: () => state,
+      onStateChange: observer.onStateChange,
+    } as Pick<
+      ExcalidrawImperativeAPI,
+      "isDestroyed" | "getAppState" | "onStateChange"
+    > as ExcalidrawImperativeAPI,
+    updateAppState: (partial: Partial<AppState>) => {
+      const prevState = state;
+      state = { ...state, ...partial };
+      observer.flush(prevState);
+    },
+  };
+};
+
+describe("app state hooks", () => {
+  afterEach(() => {
+    cleanup();
+  });
+
+  it("useAppStateValue rerenders when the selected value changes", () => {
+    const renderSpy = vi.fn();
+    const { api, updateAppState } = createMockAPI(createAppState());
+
+    const ValueConsumer = () => {
+      const value = useAppStateValue("viewModeEnabled");
+      renderSpy(value);
+      return <div data-testid="value">{String(value)}</div>;
+    };
+
+    render(
+      <ExcalidrawAPIContext.Provider value={api}>
+        <ValueConsumer />
+      </ExcalidrawAPIContext.Provider>,
+    );
+
+    expect(screen.getByTestId("value").textContent).toBe("false");
+    expect(renderSpy).toHaveBeenCalledTimes(1);
+
+    act(() => {
+      updateAppState({ viewModeEnabled: true });
+    });
+
+    expect(screen.getByTestId("value").textContent).toBe("true");
+    expect(renderSpy).toHaveBeenCalledTimes(2);
+  });
+
+  it("useOnAppStateChange notifies without rerendering", () => {
+    const renderSpy = vi.fn();
+    const callback = vi.fn();
+    const { api, updateAppState } = createMockAPI(createAppState());
+
+    const ChangeConsumer = () => {
+      const value = useOnAppStateChange("viewModeEnabled", callback);
+      renderSpy(value);
+      return <div data-testid="value">{String(value)}</div>;
+    };
+
+    render(
+      <ExcalidrawAPIContext.Provider value={api}>
+        <ChangeConsumer />
+      </ExcalidrawAPIContext.Provider>,
+    );
+
+    expect(screen.getByTestId("value").textContent).toBe("undefined");
+    expect(renderSpy).toHaveBeenCalledTimes(1);
+    expect(callback).toHaveBeenCalledTimes(1);
+    expect(callback).toHaveBeenCalledWith(
+      false,
+      expect.objectContaining({ viewModeEnabled: false }),
+    );
+
+    act(() => {
+      updateAppState({ viewModeEnabled: true });
+    });
+
+    expect(renderSpy).toHaveBeenCalledTimes(1);
+    expect(callback).toHaveBeenCalledTimes(2);
+    expect(callback).toHaveBeenLastCalledWith(
+      true,
+      expect.objectContaining({ viewModeEnabled: true }),
+    );
+  });
+});

packages/excalidraw/tests/clipboard.test.tsx

@@ -28,7 +28,9 @@ const { h } = window;
 const mouse = new Pointer("mouse");
 
 vi.mock("@excalidraw/common", async (importOriginal) => {
-  const module: any = await importOriginal();
+  const module = await importOriginal<typeof import("@excalidraw/common")>();
+  const { mockThrottleRAF } = await import("./helpers/mocks");
+
   return {
     __esmodule: true,
     ...module,
@@ -37,6 +39,7 @@ vi.mock("@excalidraw/common", async (importOriginal) => {
       ...module.KEYS,
       CTRL_OR_CMD: "ctrlKey",
     },
+    throttleRAF: mockThrottleRAF,
   };
 });
 

packages/excalidraw/tests/data/restore.test.ts

@@ -200,6 +200,26 @@ describe("restoreElements", () => {
     });
   });
 
+  it("should normalize legacy crowfoot arrowheads on restore", () => {
+    const arrowElement = API.createElement({
+      type: "arrow",
+    });
+
+    const restoredArrow = restore.restoreElements(
+      [
+        {
+          ...arrowElement,
+          startArrowhead: "crowfoot_one",
+          endArrowhead: "crowfoot_one_or_many",
+        } as any,
+      ],
+      null,
+    )[0] as ExcalidrawLinearElement;
+
+    expect(restoredArrow.startArrowhead).toBe("cardinality_one");
+    expect(restoredArrow.endArrowhead).toBe("cardinality_one_or_many");
+  });
+
   it("should strip element if restore fails", () => {
     const rect1 = API.createElement({
       type: "rectangle",

packages/excalidraw/tests/excalidraw.test.tsx

@@ -6,8 +6,16 @@ import { THEME } from "@excalidraw/common";
 
 import { t } from "../i18n";
 import { Excalidraw, Footer, MainMenu } from "../index";
+import { actionExportWithDarkMode } from "../actions/actionExport";
 
-import { fireEvent, GlobalTestState, toggleMenu, render } from "./test-utils";
+import {
+  act,
+  fireEvent,
+  GlobalTestState,
+  toggleMenu,
+  render,
+  waitFor,
+} from "./test-utils";
 
 const { h } = window;
 
@@ -304,6 +312,47 @@ describe("<Excalidraw/>", () => {
       const darkModeToggle = queryByTestId(container, "toggle-dark-mode");
       expect(darkModeToggle).toBe(null);
     });
+
+    it("should sync export theme with the UI theme when there is no session override", async () => {
+      await render(<Excalidraw theme={THEME.DARK} />);
+
+      expect(h.state.exportWithDarkMode).toBe(true);
+
+      act(() => {
+        h.setState({ exportWithDarkMode: false });
+      });
+
+      await waitFor(() => {
+        expect(h.state.exportWithDarkMode).toBe(true);
+      });
+    });
+
+    it("should keep the export theme override for the current session", async () => {
+      await render(<Excalidraw theme={THEME.LIGHT} />);
+
+      act(() => {
+        (h.app as any).actionManager.executeAction(
+          actionExportWithDarkMode,
+          "ui",
+          true,
+        );
+      });
+
+      expect(h.app.sessionExportThemeOverride).toBe(THEME.DARK);
+      expect(h.state.exportWithDarkMode).toBe(true);
+
+      act(() => {
+        h.setState({ theme: THEME.DARK });
+      });
+
+      act(() => {
+        h.setState({ theme: THEME.LIGHT });
+      });
+
+      await waitFor(() => {
+        expect(h.state.exportWithDarkMode).toBe(true);
+      });
+    });
   });
 
   describe("Test name prop", () => {

packages/excalidraw/tests/helpers/mocks.ts

@@ -3,6 +3,25 @@ import React from "react";
 import { vi } from "vitest";
 
 import type { parseMermaidToExcalidraw } from "@excalidraw/mermaid-to-excalidraw";
+import type { throttleRAF as throttleRAFType } from "@excalidraw/common";
+
+type ThrottledFn<T extends unknown[]> = ((...args: T) => void) & {
+  flush: () => void;
+  cancel: () => void;
+};
+
+export const mockThrottleRAF: typeof throttleRAFType = <T extends unknown[]>(
+  fn: (...args: T) => void,
+) => {
+  const ret = ((...args: T) => {
+    fn(...args);
+  }) as ThrottledFn<T>;
+
+  ret.flush = () => {};
+  ret.cancel = () => {};
+
+  return ret;
+};
 
 export const mockMermaidToExcalidraw = (opts: {
   parseMermaidToExcalidraw: typeof parseMermaidToExcalidraw;

packages/excalidraw/tests/packages/events.test.tsx

@@ -6,7 +6,7 @@ import { resolvablePromise } from "@excalidraw/common";
 import { Excalidraw, CaptureUpdateAction } from "../../index";
 import { API } from "../helpers/api";
 import { Pointer } from "../helpers/ui";
-import { render } from "../test-utils";
+import { render, unmountComponent } from "../test-utils";
 
 import type { ExcalidrawImperativeAPI } from "../../types";
 
@@ -21,12 +21,93 @@ describe("event callbacks", () => {
     const excalidrawAPIPromise = resolvablePromise<ExcalidrawImperativeAPI>();
     await render(
       <Excalidraw
-        excalidrawAPI={(api) => excalidrawAPIPromise.resolve(api as any)}
+        onExcalidrawAPI={(api) => excalidrawAPIPromise.resolve(api as any)}
       />,
     );
     excalidrawAPI = await excalidrawAPIPromise;
   });
 
+  it("should resolve editor:mount/editor:initialize when subscribed before mount", async () => {
+    unmountComponent();
+
+    const lifecyclePromise = resolvablePromise<{
+      api: ExcalidrawImperativeAPI;
+      mount: Promise<{
+        excalidrawAPI: ExcalidrawImperativeAPI;
+        container: HTMLDivElement | null;
+      }>;
+      initialize: Promise<ExcalidrawImperativeAPI>;
+    }>();
+
+    await render(
+      <Excalidraw
+        onExcalidrawAPI={(api) => {
+          if (api) {
+            lifecyclePromise.resolve({
+              api,
+              mount: api.onEvent("editor:mount"),
+              initialize: api.onEvent("editor:initialize"),
+            });
+          }
+        }}
+      />,
+    );
+
+    const { api, mount, initialize } = await lifecyclePromise;
+    await expect(mount).resolves.toEqual({
+      excalidrawAPI: api,
+      container: expect.any(HTMLDivElement),
+    });
+    await expect(initialize).resolves.toBe(api);
+  });
+
+  it("should replay editor:mount/editor:initialize to late subscribers", async () => {
+    const onMount = vi.fn();
+    const onInitialize = vi.fn();
+
+    excalidrawAPI.onEvent("editor:mount", onMount);
+    excalidrawAPI.onEvent("editor:initialize", onInitialize);
+
+    await Promise.resolve();
+
+    expect(onMount).toHaveBeenCalledTimes(1);
+    expect(onMount).toHaveBeenCalledWith({
+      excalidrawAPI,
+      container: expect.any(HTMLDivElement),
+    });
+    expect(onInitialize).toHaveBeenCalledTimes(1);
+    expect(onInitialize).toHaveBeenCalledWith(excalidrawAPI);
+
+    await expect(excalidrawAPI.onEvent("editor:mount")).resolves.toEqual({
+      excalidrawAPI,
+      container: expect.any(HTMLDivElement),
+    });
+    await expect(excalidrawAPI.onEvent("editor:initialize")).resolves.toBe(
+      excalidrawAPI,
+    );
+  });
+
+  it("should call onMount before onInitialize props", async () => {
+    unmountComponent();
+
+    const calls: string[] = [];
+
+    await render(
+      <Excalidraw
+        onMount={({ excalidrawAPI, container }) => {
+          expect(excalidrawAPI).toBeDefined();
+          expect(container).toBeInstanceOf(HTMLDivElement);
+          calls.push("mount");
+        }}
+        onInitialize={() => {
+          calls.push("initialize");
+        }}
+      />,
+    );
+
+    expect(calls).toEqual(["mount", "initialize"]);
+  });
+
   it("should trigger onChange on render", async () => {
     const onChange = vi.fn();
 

packages/excalidraw/tests/tool.test.tsx

@@ -20,7 +20,7 @@ describe("setActiveTool()", () => {
     const excalidrawAPIPromise = resolvablePromise<ExcalidrawImperativeAPI>();
     await render(
       <Excalidraw
-        excalidrawAPI={(api) => excalidrawAPIPromise.resolve(api as any)}
+        onExcalidrawAPI={(api) => excalidrawAPIPromise.resolve(api as any)}
       />,
     );
     excalidrawAPI = await excalidrawAPIPromise;

packages/excalidraw/types.ts

@@ -53,7 +53,6 @@ import type { Spreadsheet } from "./charts";
 import type { ClipboardData } from "./clipboard";
 import type App from "./components/App";
 import type Library from "./data/library";
-import type { FileSystemHandle } from "./data/filesystem";
 import type { ContextMenuItems } from "./components/ContextMenu";
 import type { SnapLine } from "./snapping";
 import type { ImportedDataState } from "./data/types";
@@ -408,7 +407,11 @@ export interface AppState {
   previousSelectedElementIds: { [id: string]: true };
   selectedElementsAreBeingDragged: boolean;
   shouldCacheIgnoreZoom: boolean;
-  toast: { message: string; closable?: boolean; duration?: number } | null;
+  toast: {
+    message: React.ReactNode;
+    closable?: boolean;
+    duration?: number;
+  } | null;
   zenModeEnabled: boolean;
   theme: Theme;
   /** grid cell px size */
@@ -427,7 +430,7 @@ export interface AppState {
   offsetTop: number;
   offsetLeft: number;
 
-  fileHandle: FileSystemHandle | null;
+  fileHandle: FileSystemFileHandle | null;
   collaborators: Map<SocketId, Collaborator>;
   stats: {
     open: boolean;
@@ -546,17 +549,43 @@ export type OnUserFollowedPayload = {
   action: "FOLLOW" | "UNFOLLOW";
 };
 
+export type OnExportProgress = {
+  type: "progress";
+  message?: React.ReactNode;
+  /** 0-1 range */
+  progress?: number;
+};
+
 export interface ExcalidrawProps {
   onChange?: (
     elements: readonly OrderedExcalidrawElement[],
     appState: AppState,
     files: BinaryFiles,
   ) => void;
+  /**
+   * note: only subscribes if the props.onIncrement is defined on initial render
+   */
   onIncrement?: (event: DurableIncrement | EphemeralIncrement) => void;
   initialData?:
     | (() => MaybePromise<ExcalidrawInitialDataState | null>)
     | MaybePromise<ExcalidrawInitialDataState | null>;
-  excalidrawAPI?: (api: ExcalidrawImperativeAPI) => void;
+  /**
+   * Invoked as soon as the Excalidraw API is available
+   * NOTE editor is not yet mounted, and state is not yet initialized
+   */
+  onExcalidrawAPI?: (api: ExcalidrawImperativeAPI | null) => void;
+  /**
+   * Invoked once the editor root is mounted.
+   */
+  onMount?: (payload: ExcalidrawMountPayload) => void;
+  /**
+   * Invoked when the editor root is unmounted.
+   */
+  onUnmount?: () => void;
+  /**
+   * Invoked once the initial scene is loaded.
+   */
+  onInitialize?: (api: ExcalidrawImperativeAPI) => void;
   isCollaborating?: boolean;
   onPointerUpdate?: (payload: {
     pointer: { x: number; y: number; tool: "pointer" | "laser" };
@@ -641,6 +670,32 @@ export interface ExcalidrawProps {
   aiEnabled?: boolean;
   showDeprecatedFonts?: boolean;
   renderScrollbars?: boolean;
+  /**
+   * Called before exporting to a file.
+   *
+   * Allows the host app to intercept and delay saving until async operations
+   * (e.g., images are loaded) complete.
+   *
+   * If Promise/AsyncGenerator is returned, a progress toast will be shown
+   * until the operation completes. Generator can yield progress updates.
+   */
+  onExport?: (
+    /** type of export. Currently we only call for JSON exports or
+     * JSON-embedded PNG (which is also identified as `json` type here)*/
+    type: "json",
+    data: {
+      elements: readonly ExcalidrawElement[];
+      appState: AppState;
+      files: BinaryFiles;
+    },
+    options: {
+      /** signal that gets aborted if user cancels the export (e.g. closes
+       * the native file picker dialog). In that case, you can either
+       * return immediately, or throw AbortError.
+       */
+      signal: AbortSignal;
+    },
+  ) => MaybePromise<void> | AsyncGenerator<OnExportProgress, void>;
 }
 
 export type SceneData = {
@@ -719,6 +774,8 @@ export type AppProps = Merge<
 export type AppClassProperties = {
   props: AppProps;
   state: AppState;
+  api: App["api"];
+  sessionExportThemeOverride: App["sessionExportThemeOverride"];
   interactiveCanvas: HTMLCanvasElement | null;
   /** static canvas */
   canvas: HTMLCanvasElement;
@@ -763,9 +820,13 @@ export type AppClassProperties = {
   onPointerUpEmitter: App["onPointerUpEmitter"];
   updateEditorAtom: App["updateEditorAtom"];
   onPointerDownEmitter: App["onPointerDownEmitter"];
+  onEvent: App["onEvent"];
+  onStateChange: App["onStateChange"];
 
   lastPointerMoveCoords: App["lastPointerMoveCoords"];
   bindModeHandler: App["bindModeHandler"];
+
+  setAppState: App["setAppState"];
 };
 
 export type PointerDownState = Readonly<{
@@ -838,7 +899,24 @@ export type PointerDownState = Readonly<{
 
 export type UnsubscribeCallback = () => void;
 
+export type ExcalidrawMountPayload = {
+  excalidrawAPI: ExcalidrawImperativeAPI;
+  /*
+   *Excalidraw container.
+   * should never be null, but just to be safe
+   */
+  container: HTMLDivElement | null;
+};
+
+export type ExcalidrawImperativeAPIEventMap = {
+  "editor:mount": [payload: ExcalidrawMountPayload];
+  "editor:initialize": [api: ExcalidrawImperativeAPI];
+  "editor:unmount": [];
+};
+
 export interface ExcalidrawImperativeAPI {
+  /** Whether the editor has been unmounted and the API is no longer usable. */
+  isDestroyed: boolean;
   updateScene: InstanceType<typeof App>["updateScene"];
   applyDeltas: InstanceType<typeof App>["applyDeltas"];
   mutateElement: InstanceType<typeof App>["mutateElement"];
@@ -904,6 +982,8 @@ export interface ExcalidrawImperativeAPI {
   onUserFollow: (
     callback: (payload: OnUserFollowedPayload) => void,
   ) => UnsubscribeCallback;
+  onStateChange: InstanceType<typeof App>["onStateChange"];
+  onEvent: InstanceType<typeof App>["onEvent"];
 }
 
 export type FrameNameBounds = {

packages/utils/package.json

@@ -50,7 +50,7 @@
   "dependencies": {
     "@braintree/sanitize-url": "6.0.2",
     "@excalidraw/laser-pointer": "1.3.1",
-    "browser-fs-access": "0.29.1",
+    "browser-fs-access": "0.38.0",
     "pako": "2.0.3",
     "perfect-freehand": "1.2.0",
     "png-chunk-text": "1.0.0",

setupTests.ts

@@ -6,9 +6,19 @@ import "@testing-library/jest-dom";
 import { vi } from "vitest";
 
 import polyfill from "./packages/excalidraw/polyfill";
+import { mockThrottleRAF } from "./packages/excalidraw/tests/helpers/mocks";
 import { yellow } from "./packages/excalidraw/tests/helpers/colorize";
 import { testPolyfills } from "./packages/excalidraw/tests/helpers/polyfills";
 
+vi.mock("@excalidraw/common", async (importOriginal) => {
+  const module = await importOriginal<typeof import("@excalidraw/common")>();
+
+  return {
+    ...module,
+    throttleRAF: mockThrottleRAF,
+  };
+});
+
 // mock for pep.js not working with setPointerCapture()
 HTMLElement.prototype.setPointerCapture = vi.fn();
 

yarn.lock

@@ -1095,6 +1095,45 @@
   resolved "https://registry.yarnpkg.com/@chevrotain/utils/-/utils-11.0.3.tgz#e39999307b102cff3645ec4f5b3665f5297a2224"
   integrity sha512-YslZMgtJUyuMbZ+aKvfF3x1f5liK4mWNxghFRv7jqRR9C3R3fAOGTTKvxXDa2Y1s9zSbcpuO0cAxDYsc9SrXoQ==
 
+"@codemirror/commands@^6.0.0":
+  version "6.10.2"
+  resolved "https://registry.yarnpkg.com/@codemirror/commands/-/commands-6.10.2.tgz#338bf53ab146de7bb26da4a1d32c6a6ff4d36b39"
+  integrity sha512-vvX1fsih9HledO1c9zdotZYUZnE4xV0m6i3m25s5DIfXofuprk6cRcLUZvSk3CASUbwjQX21tOGbkY2BH8TpnQ==
+  dependencies:
+    "@codemirror/language" "^6.0.0"
+    "@codemirror/state" "^6.4.0"
+    "@codemirror/view" "^6.27.0"
+    "@lezer/common" "^1.1.0"
+
+"@codemirror/language@^6.0.0":
+  version "6.12.2"
+  resolved "https://registry.yarnpkg.com/@codemirror/language/-/language-6.12.2.tgz#7db5a46757411cf251e8f450474c05710c27d42c"
+  integrity sha512-jEPmz2nGGDxhRTg3lTpzmIyGKxz3Gp3SJES4b0nAuE5SWQoKdT5GoQ69cwMmFd+wvFUhYirtDTr0/DRHpQAyWg==
+  dependencies:
+    "@codemirror/state" "^6.0.0"
+    "@codemirror/view" "^6.23.0"
+    "@lezer/common" "^1.5.0"
+    "@lezer/highlight" "^1.0.0"
+    "@lezer/lr" "^1.0.0"
+    style-mod "^4.0.0"
+
+"@codemirror/state@^6.0.0", "@codemirror/state@^6.4.0", "@codemirror/state@^6.5.0":
+  version "6.5.4"
+  resolved "https://registry.yarnpkg.com/@codemirror/state/-/state-6.5.4.tgz#f5be4b8c0d2310180d5f15a9f641c21ca69faf19"
+  integrity sha512-8y7xqG/hpB53l25CIoit9/ngxdfoG+fx+V3SHBrinnhOtLvKHRyAJJuHzkWrR4YXXLX8eXBsejgAAxHUOdW1yw==
+  dependencies:
+    "@marijn/find-cluster-break" "^1.0.0"
+
+"@codemirror/view@^6.0.0", "@codemirror/view@^6.23.0", "@codemirror/view@^6.27.0":
+  version "6.39.16"
+  resolved "https://registry.yarnpkg.com/@codemirror/view/-/view-6.39.16.tgz#e9d876aba20b31df7858abd7c2a845319c70b302"
+  integrity sha512-m6S22fFpKtOWhq8HuhzsI1WzUP/hB9THbDj0Tl5KX4gbO6Y91hwBl7Yky33NdvB6IffuRFiBxf1R8kJMyXmA4Q==
+  dependencies:
+    "@codemirror/state" "^6.5.0"
+    crelt "^1.0.6"
+    style-mod "^4.1.0"
+    w3c-keyname "^2.2.4"
+
 "@esbuild/aix-ppc64@0.19.10":
   version "0.19.10"
   resolved "https://registry.yarnpkg.com/@esbuild/aix-ppc64/-/aix-ppc64-0.19.10.tgz#fb3922a0183d27446de00cf60d4f7baaadf98d84"
@@ -1492,10 +1531,10 @@
   resolved "https://registry.yarnpkg.com/@excalidraw/markdown-to-text/-/markdown-to-text-0.1.2.tgz#1703705e7da608cf478f17bfe96fb295f55a23eb"
   integrity sha512-1nDXBNAojfi3oSFwJswKREkFm5wrSjqay81QlyRv2pkITG/XYB5v+oChENVBQLcxQwX4IUATWvXM5BcaNhPiIg==
 
-"@excalidraw/mermaid-to-excalidraw@2.0.0-rfc3":
-  version "2.0.0-rfc3"
-  resolved "https://registry.yarnpkg.com/@excalidraw/mermaid-to-excalidraw/-/mermaid-to-excalidraw-2.0.0-rfc3.tgz#2aed27280b135086d3d23878e66751819f47c3d4"
-  integrity sha512-OlKySL2aZwxgvO0wKpjq5fNNWWYwYGQAVMqwG3CJZ/zEf9NotTtX+Rl/WgL6qWvNgDq8/mavOnEstC+42gqnIQ==
+"@excalidraw/mermaid-to-excalidraw@2.1.0":
+  version "2.1.0"
+  resolved "https://registry.yarnpkg.com/@excalidraw/mermaid-to-excalidraw/-/mermaid-to-excalidraw-2.1.0.tgz#a5b9cf87c3185558cda7f9687d87b9937f452358"
+  integrity sha512-RMd+c2b7WzzUjhERMpKwp8PhF2/XlHDjr/zK+Gxfp8K9sVlafPYJ5OEa/GkN6edi2rBUXRfW+41WdO6L56b6Kw==
   dependencies:
     "@excalidraw/markdown-to-text" "0.1.2"
     "@mermaid-js/parser" "^0.6.3"
@@ -2045,6 +2084,30 @@
     "@jridgewell/resolve-uri" "^3.1.0"
     "@jridgewell/sourcemap-codec" "^1.4.14"
 
+"@lezer/common@^1.0.0", "@lezer/common@^1.1.0", "@lezer/common@^1.3.0", "@lezer/common@^1.5.0":
+  version "1.5.1"
+  resolved "https://registry.yarnpkg.com/@lezer/common/-/common-1.5.1.tgz#6e8c114ff5d36a41148e146a253734d3bb8807d3"
+  integrity sha512-6YRVG9vBkaY7p1IVxL4s44n5nUnaNnGM2/AckNgYOnxTG2kWh1vR8BMxPseWPjRNpb5VtXnMpeYAEAADoRV1Iw==
+
+"@lezer/highlight@^1.0.0":
+  version "1.2.3"
+  resolved "https://registry.yarnpkg.com/@lezer/highlight/-/highlight-1.2.3.tgz#a20f324b71148a2ea9ba6ff42e58bbfaec702857"
+  integrity sha512-qXdH7UqTvGfdVBINrgKhDsVTJTxactNNxLk7+UMwZhU13lMHaOBlJe9Vqp907ya56Y3+ed2tlqzys7jDkTmW0g==
+  dependencies:
+    "@lezer/common" "^1.3.0"
+
+"@lezer/lr@^1.0.0":
+  version "1.4.8"
+  resolved "https://registry.yarnpkg.com/@lezer/lr/-/lr-1.4.8.tgz#333de9bc9346057323ff09beb4cda47ccc38a498"
+  integrity sha512-bPWa0Pgx69ylNlMlPvBPryqeLYQjyJjqPx+Aupm5zydLIF3NE+6MMLT8Yi23Bd9cif9VS00aUebn+6fDIGBcDA==
+  dependencies:
+    "@lezer/common" "^1.0.0"
+
+"@marijn/find-cluster-break@^1.0.0":
+  version "1.0.2"
+  resolved "https://registry.yarnpkg.com/@marijn/find-cluster-break/-/find-cluster-break-1.0.2.tgz#775374306116d51c0c500b8c4face0f9a04752d8"
+  integrity sha512-l0h88YhZFyKdXIFNfSWpyjStDjGHwZ/U7iobcK1cQQD8sejsONdQtTVU+1wVN1PBw40PiiHB1vA5S7VTfQiP9g==
+
 "@mermaid-js/parser@^0.6.3":
   version "0.6.3"
   resolved "https://registry.yarnpkg.com/@mermaid-js/parser/-/parser-0.6.3.tgz#3ce92dad2c5d696d29e11e21109c66a7886c824e"
@@ -4540,10 +4603,10 @@ braces@^3.0.3, braces@~3.0.2:
   dependencies:
     fill-range "^7.1.1"
 
-browser-fs-access@0.29.1:
-  version "0.29.1"
-  resolved "https://registry.yarnpkg.com/browser-fs-access/-/browser-fs-access-0.29.1.tgz#8a9794c73cf86b9aec74201829999c597128379c"
-  integrity sha512-LSvVX5e21LRrXqVMhqtAwj5xPgDb+fXAIH80NsnCQ9xuZPs2xWsOREi24RKgZa1XOiQRbcmVrv87+ulOKsgjxw==
+browser-fs-access@0.38.0:
+  version "0.38.0"
+  resolved "https://registry.yarnpkg.com/browser-fs-access/-/browser-fs-access-0.38.0.tgz#9024c5bf3d962287a08d14beebb86cb819cbb838"
+  integrity sha512-JveqW2w6pEZqFEEfMgCszXzYpE89dG+nPsmOdcs741mFFAROeL+iqjGEpR07RI+s0YY0EFr+4KnOoACprJTpOw==
 
 browserslist@^4.20.3, browserslist@^4.24.0, browserslist@^4.24.4:
   version "4.24.4"
@@ -4968,6 +5031,11 @@ crc-32@^0.3.0:
   resolved "https://registry.yarnpkg.com/crc-32/-/crc-32-0.3.0.tgz#6a3d3687f5baec41f7e9b99fe1953a2e5d19775e"
   integrity sha512-kucVIjOmMc1f0tv53BJ/5WIX+MGLcKuoBhnGqQrgKJNqLByb/sVMWfW/Aw6hw0jgcqjJ2pi9E5y32zOIpaUlsA==
 
+crelt@^1.0.6:
+  version "1.0.6"
+  resolved "https://registry.yarnpkg.com/crelt/-/crelt-1.0.6.tgz#7cc898ea74e190fb6ef9dae57f8f81cf7302df72"
+  integrity sha512-VQ2MBenTq1fWZUH9DJNGti7kKv6EeAuYr3cLwxUWhIu1baTaXh4Ib5W2CqHVqib4/MqbYGJqiL3Zb8GJZr3l4g==
+
 cross-env@7.0.3:
   version "7.0.3"
   resolved "https://registry.yarnpkg.com/cross-env/-/cross-env-7.0.3.tgz#865264b29677dc015ba8418918965dd232fc54cf"
@@ -9520,6 +9588,11 @@ strip-json-comments@^3.1.0, strip-json-comments@^3.1.1:
   resolved "https://registry.yarnpkg.com/strip-json-comments/-/strip-json-comments-3.1.1.tgz#31f1281b3832630434831c310c01cccda8cbe006"
   integrity sha512-6fPc+R4ihwqP6N/aIv2f1gMH8lOVtWQHoqC4yK6oSDVVocumAsfCqjkXnqiYMhmMwS/mEHLp7Vehlt3ql6lEig==
 
+style-mod@^4.0.0, style-mod@^4.1.0:
+  version "4.1.3"
+  resolved "https://registry.yarnpkg.com/style-mod/-/style-mod-4.1.3.tgz#6e9012255bb799bdac37e288f7671b5d71bf9f73"
+  integrity sha512-i/n8VsZydrugj3Iuzll8+x/00GH2vnYsk1eomD8QiRrSAeW6ItbCQDtfXCeJHd0iwiNagqjQkvpvREEPtW3IoQ==
+
 styled-jsx@5.1.1:
   version "5.1.1"
   resolved "https://registry.yarnpkg.com/styled-jsx/-/styled-jsx-5.1.1.tgz#839a1c3aaacc4e735fed0781b8619ea5d0009d1f"
@@ -10269,6 +10342,11 @@ vscode-uri@~3.0.8:
   resolved "https://registry.yarnpkg.com/vscode-uri/-/vscode-uri-3.0.8.tgz#1770938d3e72588659a172d0fd4642780083ff9f"
   integrity sha512-AyFQ0EVmsOZOlAnxoFOGOq1SQDWAB7C6aqMGS23svWAllfOaxbuFvcT8D1i8z3Gyn8fraVeZNNmN6e9bxxXkKw==
 
+w3c-keyname@^2.2.4:
+  version "2.2.8"
+  resolved "https://registry.yarnpkg.com/w3c-keyname/-/w3c-keyname-2.2.8.tgz#7b17c8c6883d4e8b86ac8aba79d39e880f8869c5"
+  integrity sha512-dpojBhNsCNN7T82Tm7k26A6G9ML3NkhDsnw9n/eoxSRlVBB4CEtIQ/KTCLI2Fwf3ataSXRhYFkQi3SlnFwPvPQ==
+
 w3c-xmlserializer@^4.0.0:
   version "4.0.0"
   resolved "https://registry.yarnpkg.com/w3c-xmlserializer/-/w3c-xmlserializer-4.0.0.tgz#aebdc84920d806222936e3cdce408e32488a3073"