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/*
Copyright 2020 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 { getOrCreatePrecacheController } from './utils/getOrCreatePrecacheController.js';
import './_version.js';
/**
* `PrecacheFallbackPlugin` allows you to specify an "offline fallback"
* response to be used when a given strategy is unable to generate a response.
*
* It does this by intercepting the `handlerDidError` plugin callback
* and returning a precached response, taking the expected revision parameter
* into account automatically.
*
* Unless you explicitly pass in a `PrecacheController` instance to the
* constructor, the default instance will be used. Generally speaking, most
* developers will end up using the default.
*
* @memberof workbox-precaching
*/
class PrecacheFallbackPlugin {
/**
* Constructs a new PrecacheFallbackPlugin with the associated fallbackURL.
*
* @param {Object} config
* @param {string} config.fallbackURL A precached URL to use as the fallback
* if the associated strategy can't generate a response.
* @param {PrecacheController} [config.precacheController] An optional
* PrecacheController instance. If not provided, the default
* PrecacheController will be used.
*/
constructor({ fallbackURL, precacheController, }) {
/**
* @return {Promise<Response>} The precache response for the fallback URL.
*
* @private
*/
this.handlerDidError = () => this._precacheController.matchPrecache(this._fallbackURL);
this._fallbackURL = fallbackURL;
this._precacheController =
precacheController || getOrCreatePrecacheController();
}
}
export { PrecacheFallbackPlugin };