message: options-based types which can be undefined
diff: @@ -12,7 +12,7 @@ declare class FilePicker<P extends FilePicker.Options = FilePicker.Options> exte
  /**
  * The full requested path given by the user
  */
  - request: string | null;
  + request: string | undefined;
  /**
  * The file sources which are available for browsing
  @@ -39,17 +39,17 @@ declare class FilePicker<P extends FilePicker.Options = FilePicker.Options> exte
  /**
  * The general file type which controls the set of extensions which will be accepted
  */
  - type: string;
  + type: string | undefined;
  /**
  * The target HTML element this file picker is bound to
  */
  - field: HTMLElement | null;
  + field: HTMLElement | undefined;
  /**
  * A button which controls the display of the picker UI
  */
  - button: HTMLElement | null;
  + button: HTMLElement | undefined;
  /**
  * The display mode of the FilePicker UI
  @@ -59,7 +59,7 @@ declare class FilePicker<P extends FilePicker.Options = FilePicker.Options> exte
  /**
  * The current set of file extensions which are being filtered upon
  */
  - extensions: string[];
  + extensions: string[] | undefined;
  protected _loaded: boolean;
  