Source: lib/util/iterables.js

  1. /**
  2.  * @license
  3.  * Copyright 2016 Google Inc.
  4.  *
  5.  * Licensed under the Apache License, Version 2.0 (the "License");
  6.  * you may not use this file except in compliance with the License.
  7.  * You may obtain a copy of the License at
  8.  *
  9.  *     http://www.apache.org/licenses/LICENSE-2.0
  10.  *
  11.  * Unless required by applicable law or agreed to in writing, software
  12.  * distributed under the License is distributed on an "AS IS" BASIS,
  13.  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  14.  * See the License for the specific language governing permissions and
  15.  * limitations under the License.
  16.  */
  18. goog.provide('shaka.util.Iterables');
  21. /**
  22.  * Recreations of Array-like functions so that they work on any iterable
  23.  * type.
  24.  * @final
  25.  */
  26. shaka.util.Iterables = class {
  27.   /**
  28.    * @param {!Iterable.<FROM>|!Iterator.<FROM>} iterable
  29.    * @param {function(FROM):TO} mapping
  30.    * @return {!Iterable.<TO>}
  31.    * @template FROM,TO
  32.    */
  33.   static map(iterable, mapping) {
  34.     const array = [];
  35.     for (const x of iterable) { array.push(mapping(x)); }
  36.     return array;
  37.   }
  39.   /**
  40.    * @param {!Iterable.<T>|!Iterator.<T>} iterable
  41.    * @param {function(T):boolean} test
  42.    * @return {boolean}
  43.    * @template T
  44.    */
  45.   static every(iterable, test) {
  46.     for (const x of iterable) {
  47.       if (!test(x)) { return false; }
  48.     }
  49.     return true;
  50.   }
  52.   /**
  53.    * @param {!Iterable.<T>|!Iterator.<T>} iterable
  54.    * @param {function(T):boolean} test
  55.    * @return {boolean}
  56.    * @template T
  57.    */
  58.   static some(iterable, test) {
  59.     for (const x of iterable) {
  60.       if (test(x)) { return true; }
  61.     }
  62.     return false;
  63.   }
  64. };