/*
 Copyright 2018 Google Inc. All Rights Reserved.
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
 You may obtain a copy of the License at

     http://www.apache.org/licenses/LICENSE-2.0

 Unless required by applicable law or agreed to in writing, software
 distributed under the License is distributed on an "AS IS" BASIS,
 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 See the License for the specific language governing permissions and
 limitations under the License.
*/

import './_version.mjs';

let cachedIsSupported = undefined;

/**
 * This is a utility method that determines whether the current browser supports
 * the features required to create streamed responses. Currently, it checks if
 * [`ReadableStream`](https://developer.mozilla.org/en-US/docs/Web/API/ReadableStream/ReadableStream)
 * can be created.
 *
 * @return {boolean} `true`, if the current browser meets the requirements for
 * streaming responses, and `false` otherwise.
 *
 * @memberof workbox.streams
 */
function isSupported() {
  if (cachedIsSupported === undefined) {
    // See https://github.com/GoogleChrome/workbox/issues/1473
    try {
      new ReadableStream({start() {}});
      cachedIsSupported = true;
    } catch (error) {
      cachedIsSupported = false;
    }
  }

  return cachedIsSupported;
}

export {isSupported};