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197 lines
7.8 KiB
197 lines
7.8 KiB
/* |
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Copyright 2018 Google LLC |
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Use of this source code is governed by an MIT-style |
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license that can be found in the LICENSE file or at |
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https://opensource.org/licenses/MIT. |
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*/ |
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import { assert } from 'workbox-core/_private/assert.js'; |
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import { logger } from 'workbox-core/_private/logger.js'; |
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import { WorkboxError } from 'workbox-core/_private/WorkboxError.js'; |
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import { cacheOkAndOpaquePlugin } from './plugins/cacheOkAndOpaquePlugin.js'; |
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import { Strategy } from './Strategy.js'; |
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import { messages } from './utils/messages.js'; |
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import './_version.js'; |
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/** |
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* An implementation of a |
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* [network first](https://developer.chrome.com/docs/workbox/caching-strategies-overview/#network-first-falling-back-to-cache) |
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* request strategy. |
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* |
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* By default, this strategy will cache responses with a 200 status code as |
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* well as [opaque responses](https://developer.chrome.com/docs/workbox/caching-resources-during-runtime/#opaque-responses). |
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* Opaque responses are are cross-origin requests where the response doesn't |
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* support [CORS](https://enable-cors.org/). |
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* |
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* If the network request fails, and there is no cache match, this will throw |
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* a `WorkboxError` exception. |
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* |
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* @extends workbox-strategies.Strategy |
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* @memberof workbox-strategies |
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*/ |
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class NetworkFirst extends Strategy { |
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/** |
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* @param {Object} [options] |
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* @param {string} [options.cacheName] Cache name to store and retrieve |
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* requests. Defaults to cache names provided by |
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* {@link workbox-core.cacheNames}. |
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* @param {Array<Object>} [options.plugins] [Plugins]{@link https://developers.google.com/web/tools/workbox/guides/using-plugins} |
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* to use in conjunction with this caching strategy. |
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* @param {Object} [options.fetchOptions] Values passed along to the |
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* [`init`](https://developer.mozilla.org/en-US/docs/Web/API/WindowOrWorkerGlobalScope/fetch#Parameters) |
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* of [non-navigation](https://github.com/GoogleChrome/workbox/issues/1796) |
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* `fetch()` requests made by this strategy. |
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* @param {Object} [options.matchOptions] [`CacheQueryOptions`](https://w3c.github.io/ServiceWorker/#dictdef-cachequeryoptions) |
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* @param {number} [options.networkTimeoutSeconds] If set, any network requests |
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* that fail to respond within the timeout will fallback to the cache. |
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* |
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* This option can be used to combat |
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* "[lie-fi]{@link https://developers.google.com/web/fundamentals/performance/poor-connectivity/#lie-fi}" |
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* scenarios. |
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*/ |
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constructor(options = {}) { |
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super(options); |
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// If this instance contains no plugins with a 'cacheWillUpdate' callback, |
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// prepend the `cacheOkAndOpaquePlugin` plugin to the plugins list. |
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if (!this.plugins.some((p) => 'cacheWillUpdate' in p)) { |
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this.plugins.unshift(cacheOkAndOpaquePlugin); |
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} |
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this._networkTimeoutSeconds = options.networkTimeoutSeconds || 0; |
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if (process.env.NODE_ENV !== 'production') { |
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if (this._networkTimeoutSeconds) { |
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assert.isType(this._networkTimeoutSeconds, 'number', { |
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moduleName: 'workbox-strategies', |
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className: this.constructor.name, |
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funcName: 'constructor', |
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paramName: 'networkTimeoutSeconds', |
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}); |
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} |
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} |
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} |
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/** |
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* @private |
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* @param {Request|string} request A request to run this strategy for. |
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* @param {workbox-strategies.StrategyHandler} handler The event that |
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* triggered the request. |
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* @return {Promise<Response>} |
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*/ |
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async _handle(request, handler) { |
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const logs = []; |
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if (process.env.NODE_ENV !== 'production') { |
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assert.isInstance(request, Request, { |
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moduleName: 'workbox-strategies', |
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className: this.constructor.name, |
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funcName: 'handle', |
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paramName: 'makeRequest', |
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}); |
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} |
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const promises = []; |
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let timeoutId; |
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if (this._networkTimeoutSeconds) { |
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const { id, promise } = this._getTimeoutPromise({ request, logs, handler }); |
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timeoutId = id; |
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promises.push(promise); |
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} |
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const networkPromise = this._getNetworkPromise({ |
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timeoutId, |
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request, |
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logs, |
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handler, |
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}); |
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promises.push(networkPromise); |
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const response = await handler.waitUntil((async () => { |
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// Promise.race() will resolve as soon as the first promise resolves. |
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return ((await handler.waitUntil(Promise.race(promises))) || |
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// If Promise.race() resolved with null, it might be due to a network |
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// timeout + a cache miss. If that were to happen, we'd rather wait until |
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// the networkPromise resolves instead of returning null. |
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// Note that it's fine to await an already-resolved promise, so we don't |
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// have to check to see if it's still "in flight". |
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(await networkPromise)); |
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})()); |
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if (process.env.NODE_ENV !== 'production') { |
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logger.groupCollapsed(messages.strategyStart(this.constructor.name, request)); |
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for (const log of logs) { |
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logger.log(log); |
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} |
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messages.printFinalResponse(response); |
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logger.groupEnd(); |
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} |
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if (!response) { |
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throw new WorkboxError('no-response', { url: request.url }); |
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} |
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return response; |
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} |
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/** |
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* @param {Object} options |
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* @param {Request} options.request |
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* @param {Array} options.logs A reference to the logs array |
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* @param {Event} options.event |
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* @return {Promise<Response>} |
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* |
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* @private |
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*/ |
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_getTimeoutPromise({ request, logs, handler, }) { |
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let timeoutId; |
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const timeoutPromise = new Promise((resolve) => { |
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const onNetworkTimeout = async () => { |
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if (process.env.NODE_ENV !== 'production') { |
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logs.push(`Timing out the network response at ` + |
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`${this._networkTimeoutSeconds} seconds.`); |
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} |
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resolve(await handler.cacheMatch(request)); |
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}; |
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timeoutId = setTimeout(onNetworkTimeout, this._networkTimeoutSeconds * 1000); |
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}); |
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return { |
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promise: timeoutPromise, |
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id: timeoutId, |
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}; |
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} |
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/** |
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* @param {Object} options |
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* @param {number|undefined} options.timeoutId |
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* @param {Request} options.request |
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* @param {Array} options.logs A reference to the logs Array. |
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* @param {Event} options.event |
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* @return {Promise<Response>} |
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* |
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* @private |
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*/ |
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async _getNetworkPromise({ timeoutId, request, logs, handler, }) { |
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let error; |
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let response; |
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try { |
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response = await handler.fetchAndCachePut(request); |
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} |
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catch (fetchError) { |
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if (fetchError instanceof Error) { |
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error = fetchError; |
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} |
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} |
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if (timeoutId) { |
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clearTimeout(timeoutId); |
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} |
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if (process.env.NODE_ENV !== 'production') { |
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if (response) { |
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logs.push(`Got response from network.`); |
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} |
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else { |
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logs.push(`Unable to get a response from the network. Will respond ` + |
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`with a cached response.`); |
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} |
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} |
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if (error || !response) { |
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response = await handler.cacheMatch(request); |
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if (process.env.NODE_ENV !== 'production') { |
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if (response) { |
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logs.push(`Found a cached response in the '${this.cacheName}'` + ` cache.`); |
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} |
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else { |
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logs.push(`No response found in the '${this.cacheName}' cache.`); |
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} |
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} |
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} |
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return response; |
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} |
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} |
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export { NetworkFirst };
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