Persistence

• File storage (default): Room state is persisted to data/excalidraw-rooms/{roomId}/ (scene.json + files/). Rooms survive server restarts. handleExcalidrawStream auto-registers this when no custom callbacks are set.

• In-memory only: Pass persist: false to handleExcalidrawStream for demos or local-only flows. When the last peer leaves, the room is torn down.

• Custom: Wire setLoadCallback / setPersistCallback (from svelte-excalidraw/server/state) in your hooks before the first request to use your own storage.

Custom storage example

In src/hooks.server.ts, call the setters once at startup:

import { setLoadCallback, setPersistCallback } from "svelte-excalidraw/server/state";

setLoadCallback((roomId) => {
  const stored = myDb.getRoom(roomId);
  return stored ? { elements: stored.elements, files: stored.files } : null;
});

setPersistCallback((roomId, doc) => {
  myDb.saveRoom(roomId, { elements: doc.elements, files: doc.files });
});

RoomDocument is { elements: ElementLike[]; files: Record<string, unknown> }. Persist is debounced by the server; your callback receives updates after changes. For file storage (images, etc.), use registerFileStorage from the same package or implement your own via the callbacks.