46 lines
1.4 KiB
JavaScript
46 lines
1.4 KiB
JavaScript
|
/*
|
||
|
|
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};
|