chromium/src/third_party/blink/renderer/modules/file_system_access/file_system_file_handle.idl

// Copyright 2018 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

// https://wicg.github.io/file-system-access/#filesystemfilehandle
[
    Exposed=(Window,Worker),
    SecureContext,
    Serializable,
    RuntimeEnabled=FileSystemAccess
] interface FileSystemFileHandle : FileSystemHandle {
    [CallWith=ScriptState, RaisesException]
    Promise<FileSystemWritableFileStream> createWritable(optional FileSystemCreateWritableOptions options = {});

    [CallWith=ScriptState, RaisesException] Promise<File> getFile();
};