mirror of
https://github.com/shaka-project/shaka-player.git
synced 2026-06-23 17:27:16 +03:00
Joey Parrish
5d2dc2daaf
Since we are getting strict about semantic versioning, we can't remove features in v3.1. Any backward compatibility we offer will be maintained until v4.0. The exception is explicit IE 11 support, which will still be removed in v3.1. To help us follow the rules for removal, the Deprecate utility no longer accepts a minor version argument. Change-Id: I4dd94a6084e4ed72eeec410eb9aa0ad974d8dac8
100 lines
2.5 KiB
JavaScript
100 lines
2.5 KiB
JavaScript
/** @license
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* Copyright 2016 Google LLC
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* SPDX-License-Identifier: Apache-2.0
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*/
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goog.provide('shaka.util.Functional');
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goog.require('shaka.Deprecate');
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/**
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* @summary A set of functional utility functions.
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*/
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shaka.util.Functional = class {
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/**
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* Creates a promise chain that calls the given callback for each element in
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* the array in a catch of a promise.
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*
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* e.g.:
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* Promise.reject().catch(callback(array[0])).catch(callback(array[1]));
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*
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* @param {!Array.<ELEM>} array
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* @param {function(ELEM):!Promise.<RESULT>} callback
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* @return {!Promise.<RESULT>}
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* @template ELEM,RESULT
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*/
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static createFallbackPromiseChain(array, callback) {
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return array.reduce((promise, elem) => {
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return promise.catch(() => callback(elem));
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}, Promise.reject());
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}
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/**
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* Returns the first array concatenated to the second; used to collapse an
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* array of arrays into a single array.
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*
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* @param {!Array.<T>} all
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* @param {!Array.<T>} part
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* @return {!Array.<T>}
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* @template T
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*/
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static collapseArrays(all, part) {
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return all.concat(part);
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}
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/**
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* A no-op function that ignores its arguments. This is used to suppress
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* unused variable errors.
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* @param {...*} args
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*/
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static ignored(...args) {}
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/**
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* A no-op function. Useful in promise chains.
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*/
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static noop() {}
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/**
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* Returns if the given value is not null; useful for filtering out null
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* values.
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*
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* @param {T} value
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* @return {boolean}
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* @template T
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*/
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static isNotNull(value) {
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return value != null;
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}
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/**
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* Calls a factory function while allowing it to be a constructor for
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* reverse-compatibility.
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*
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* @param {function():!T} factory
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* @return {!T}
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* @template T
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*/
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static callFactory(factory) {
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// See https://stackoverflow.com/q/10428603/1208502
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// eslint-disable-next-line no-restricted-syntax
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const obj = Object.create(factory.prototype || Object.prototype);
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// If this is a constructor, call it with our newly created object to
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// initialize it; if this isn't a constructor, the "this" shouldn't be used
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// since it should be "undefined".
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let ret = factory.call(obj); // eslint-disable-line no-restricted-syntax
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// If it didn't return anything, assume it is a constructor and return our
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// "this" value instead.
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if (!ret) {
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shaka.Deprecate.deprecateFeature(4,
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'Factories requiring new',
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'Factories should be plain functions');
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ret = obj;
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}
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return ret;
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}
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};
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