Source: lib/util/map_utils.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.MapUtils');
  21. /**
  22.  * @namespace shaka.util.MapUtils
  23.  * @summary A set of map/object utility functions.
  24.  */
  27. /**
  28.  * Returns true if the map is empty; otherwise, returns false.
  29.  *
  30.  * @param {Object.<KEY, VALUE>} object
  31.  * @return {boolean}
  32.  * @template KEY,VALUE
  33.  */
  34. shaka.util.MapUtils.empty = function(object) {
  35.   return !object || Object.keys(object).length == 0;
  36. };
  39. /**
  40.  * Gets the map's values.
  41.  *
  42.  * @param {!Object.<KEY, VALUE>} object
  43.  * @return {!Array.<VALUE>}
  44.  * @template KEY,VALUE
  45.  */
  46. shaka.util.MapUtils.values = function(object) {
  47.   return Object.keys(object).map(function(key) { return object[key]; });
  48. };
  51. /**
  52.  * Converts the values in the given Map to a different value.
  53.  *
  54.  * @param {!Object.<KEY, VALUE>} object
  55.  * @param {function(VALUE, KEY=):OUTPUT} callback
  56.  * @return {!Object.<KEY, OUTPUT>}
  57.  * @template KEY,VALUE,OUTPUT
  58.  */
  59. shaka.util.MapUtils.map = function(object, callback) {
  60.   return Object.keys(object).reduce(function(ret, key) {
  61.     var value = object[key];
  62.     ret[key] = callback(value, key);
  63.     return ret;
  64.   }, {});
  65. };
  68. /**
  69.  * Returns true if every entry matches the predicate.
  70.  *
  71.  * @param {!Object.<KEY, VALUE>} object
  72.  * @param {function(KEY, VALUE):boolean} callback
  73.  * @return {boolean}
  74.  * @template KEY,VALUE
  75.  */
  76. shaka.util.MapUtils.every = function(object, callback) {
  77.   return Object.keys(object).every(function(key) {
  78.     return callback(key, object[key]);
  79.   });
  80. };
  83. /**
  84.  * Invokes the callback for each entry in the map.
  85.  *
  86.  * @param {!Object.<KEY, VALUE>} object
  87.  * @param {function(KEY, VALUE)} callback
  88.  * @template KEY,VALUE
  89.  */
  90. shaka.util.MapUtils.forEach = function(object, callback) {
  91.   Object.keys(object).forEach(function(key) {
  92.     callback(key, object[key]);
  93.   });
  94. };