feat: create and expose serializeLibraryAsJSON (#5009)

Co-authored-by: David Luzar <luzar.david@gmail.com>

src/packages/excalidraw/CHANGELOG.md

@@ -18,6 +18,7 @@ Please add the latest change on the top under the correct section.
 #### Refactor
 
 - Rename `appState.elementLocked` to `appState.activeTool.locked` [#4983](https://github.com/excalidraw/excalidraw/pull/4983).
+- Expose [`serializeLibraryAsJSON`](https://github.com/excalidraw/excalidraw/blob/master/src/packages/excalidraw/README.md#serializeLibraryAsJSON) helper that we use when saving Excalidraw Library to a file.
 
 ##### BREAKING CHANGE
 

src/packages/excalidraw/README_NEXT.md

@@ -906,6 +906,17 @@ serializeAsJSON({
 
 Takes the scene elements and state and returns a JSON string. Deleted `elements`as well as most properties from `AppState` are removed from the resulting JSON. (see [`serializeAsJSON()`](https://github.com/excalidraw/excalidraw/blob/master/src/data/json.ts#L16) source for details).
 
+#### `serializeLibraryAsJSON`
+
+**_Signature_**
+
+<pre>
+serializeLibraryAsJSON({
+  libraryItems: <a href="https://github.com/excalidraw/excalidraw/blob/master/src/types.ts#L191">LibraryItems[]</a>,
+</pre>
+
+Takes the library items and returns a JSON string.
+
 #### `getSceneVersion`
 
 **How to use**

src/packages/utils.ts

@@ -139,6 +139,6 @@ export const exportToSvg = async ({
   );
 };
 
-export { serializeAsJSON } from "../data/json";
+export { serializeAsJSON, serializeLibraryAsJSON } from "../data/json";
 export { loadFromBlob, loadLibraryFromBlob } from "../data/blob";
 export { getFreeDrawSvgPath } from "../renderer/renderElement";