feat: allow props.initialData to be a function (#8135)

packages/excalidraw/CHANGELOG.md

@@ -15,6 +15,8 @@ Please add the latest change on the top under the correct section.
 
 ### Features
 
+- `props.initialData` can now be a function that returns `ExcalidrawInitialDataState` or `Promise<ExcalidrawInitialDataState>`. [#8107](https://github.com/excalidraw/excalidraw/pull/8135)
+
 - Added support for multiplayer undo/redo, by calculating invertible increments and storing them inside the local-only undo/redo stacks. [#7348](https://github.com/excalidraw/excalidraw/pull/7348)
 
 - `MainMenu.DefaultItems.ToggleTheme` now supports `onSelect(theme: string)` callback, and optionally `allowSystemTheme: boolean` alongside `theme: string` to indicate you want to allow users to set to system theme (you need to handle this yourself). [#7853](https://github.com/excalidraw/excalidraw/pull/7853)

packages/excalidraw/components/App.tsx

@@ -2291,7 +2291,11 @@ class App extends React.Component<AppProps, AppState> {
     }
     let initialData = null;
     try {
-      initialData = (await this.props.initialData) || null;
+      if (typeof this.props.initialData === "function") {
+        initialData = (await this.props.initialData()) || null;
+      } else {
+        initialData = (await this.props.initialData) || null;
+      }
       if (initialData?.libraryItems) {
         this.library
           .updateLibrary({

packages/excalidraw/types.ts

@@ -444,7 +444,9 @@ export interface ExcalidrawProps {
     appState: AppState,
     files: BinaryFiles,
   ) => void;
-  initialData?: MaybePromise<ExcalidrawInitialDataState | null>;
+  initialData?:
+    | (() => MaybePromise<ExcalidrawInitialDataState | null>)
+    | MaybePromise<ExcalidrawInitialDataState | null>;
   excalidrawAPI?: (api: ExcalidrawImperativeAPI) => void;
   isCollaborating?: boolean;
   onPointerUpdate?: (payload: {