refactor(infra): directory structure (#4615)

packages/common/y-indexeddb/README.md

@@ -0,0 +1,38 @@
+# @toeverything/y-indexeddb
+
+## Features
+
+- persistence data in indexeddb
+- sub-documents support
+- fully TypeScript
+
+## Usage
+
+```ts
+import { createIndexedDBProvider, downloadBinary } from '@toeverything/y-indexeddb';
+import * as Y from 'yjs';
+
+const yDoc = new Y.Doc({
+  // we use `guid` as unique key
+  guid: 'my-doc',
+});
+
+// sync yDoc with indexedDB
+const provider = createIndexedDBProvider(yDoc);
+provider.connect();
+await provider.whenSynced.then(() => {
+  console.log('synced');
+  provider.disconnect();
+});
+
+// dowload binary data from indexedDB for once
+downloadBinary(yDoc.guid).then(blob => {
+  if (blob !== false) {
+    Y.applyUpdate(yDoc, blob);
+  }
+});
+```
+
+## LICENSE
+
+[MIT](https://github.com/toeverything/AFFiNE/blob/master/LICENSE-MIT)