Fix race condition

Author: jtpio

src/drive.ts

@@ -42,7 +42,17 @@ export class FileSystemDrive implements Contents.IDrive {
     const root = this._rootHandle;
 
     if (!root) {
-      throw new Error('Files not available');
+      return {
+        name: '',
+        path: '',
+        created: new Date().toISOString(),
+        last_modified: new Date().toISOString(),
+        format: 'json',
+        content: null,
+        writable: true,
+        type: 'directory',
+        mimetype: 'application/json'
+      };
     }
 
     if (localPath) {

src/index.ts

@@ -27,7 +27,9 @@ const plugin: JupyterFrontEndPlugin<void> = {
   ) => {
     if (!window.showDirectoryPicker) {
       // bail if the browser does not support the File System API
-      console.warn('The File System API is not supported in this browser.');
+      console.warn(
+        'The File System Access API is not supported in this browser.'
+      );
       return;
     }