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- /*
- Copyright 2018 Google LLC
- Use of this source code is governed by an MIT-style
- license that can be found in the LICENSE file or at
- https://opensource.org/licenses/MIT.
- */
- import { logger } from 'workbox-core/_private/logger.js';
- import { assert } from 'workbox-core/_private/assert.js';
- import { Deferred } from 'workbox-core/_private/Deferred.js';
- import './_version.js';
- /**
- * Takes either a Response, a ReadableStream, or a
- * [BodyInit](https://fetch.spec.whatwg.org/#bodyinit) and returns the
- * ReadableStreamReader object associated with it.
- *
- * @param {module:workbox-streams.StreamSource} source
- * @return {ReadableStreamReader}
- * @private
- */
- function _getReaderFromSource(source) {
- if (source instanceof Response) {
- return source.body.getReader();
- }
- if (source instanceof ReadableStream) {
- return source.getReader();
- }
- return new Response(source).body.getReader();
- }
- /**
- * Takes multiple source Promises, each of which could resolve to a Response, a
- * ReadableStream, or a [BodyInit](https://fetch.spec.whatwg.org/#bodyinit).
- *
- * Returns an object exposing a ReadableStream with each individual stream's
- * data returned in sequence, along with a Promise which signals when the
- * stream is finished (useful for passing to a FetchEvent's waitUntil()).
- *
- * @param {Array<Promise<module:workbox-streams.StreamSource>>} sourcePromises
- * @return {Object<{done: Promise, stream: ReadableStream}>}
- *
- * @memberof module:workbox-streams
- */
- function concatenate(sourcePromises) {
- if (process.env.NODE_ENV !== 'production') {
- assert.isArray(sourcePromises, {
- moduleName: 'workbox-streams',
- funcName: 'concatenate',
- paramName: 'sourcePromises',
- });
- }
- const readerPromises = sourcePromises.map((sourcePromise) => {
- return Promise.resolve(sourcePromise).then((source) => {
- return _getReaderFromSource(source);
- });
- });
- const streamDeferred = new Deferred();
- let i = 0;
- const logMessages = [];
- const stream = new ReadableStream({
- pull(controller) {
- return readerPromises[i]
- .then((reader) => reader.read())
- .then((result) => {
- if (result.done) {
- if (process.env.NODE_ENV !== 'production') {
- logMessages.push(['Reached the end of source:',
- sourcePromises[i]]);
- }
- i++;
- if (i >= readerPromises.length) {
- // Log all the messages in the group at once in a single group.
- if (process.env.NODE_ENV !== 'production') {
- logger.groupCollapsed(`Concatenating ${readerPromises.length} sources.`);
- for (const message of logMessages) {
- if (Array.isArray(message)) {
- logger.log(...message);
- }
- else {
- logger.log(message);
- }
- }
- logger.log('Finished reading all sources.');
- logger.groupEnd();
- }
- controller.close();
- streamDeferred.resolve();
- return;
- }
- // The `pull` method is defined because we're inside it.
- return this.pull(controller);
- }
- else {
- controller.enqueue(result.value);
- }
- }).catch((error) => {
- if (process.env.NODE_ENV !== 'production') {
- logger.error('An error occurred:', error);
- }
- streamDeferred.reject(error);
- throw error;
- });
- },
- cancel() {
- if (process.env.NODE_ENV !== 'production') {
- logger.warn('The ReadableStream was cancelled.');
- }
- streamDeferred.resolve();
- },
- });
- return { done: streamDeferred.promise, stream };
- }
- export { concatenate };
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