Source: lib/util/multi_map.js

  1. /*! @license
  2.  * Shaka Player
  3.  * Copyright 2016 Google LLC
  4.  * SPDX-License-Identifier: Apache-2.0
  5.  */
  7. goog.provide('shaka.util.MultiMap');
  10. /**
  11.  * @summary A simple multimap template.
  12.  * @template T
  13.  */
  14. shaka.util.MultiMap = class {
  15.   constructor() {
  16.     /** @private {!Object.<string, !Array.<T>>} */
  17.     this.map_ = {};
  18.   }
  21.   /**
  22.    * Add a key, value pair to the map.
  23.    * @param {string} key
  24.    * @param {T} value
  25.    */
  26.   push(key, value) {
  27.     if (this.map_.hasOwnProperty(key)) {
  28.       this.map_[key].push(value);
  29.     } else {
  30.       this.map_[key] = [value];
  31.     }
  32.   }
  35.   /**
  36.    * Get a list of values by key.
  37.    * @param {string} key
  38.    * @return {Array.<T>} or null if no such key exists.
  39.    */
  40.   get(key) {
  41.     const list = this.map_[key];
  42.     // slice() clones the list so that it and the map can each be modified
  43.     // without affecting the other.
  44.     return list ? list.slice() : null;
  45.   }
  48.   /**
  49.    * Get a list of all values.
  50.    * @return {!Array.<T>}
  51.    */
  52.   getAll() {
  53.     const list = [];
  54.     for (const key in this.map_) {
  55.       list.push(...this.map_[key]);
  56.     }
  57.     return list;
  58.   }
  61.   /**
  62.    * Remove a specific value, if it exists.
  63.    * @param {string} key
  64.    * @param {T} value
  65.    */
  66.   remove(key, value) {
  67.     if (!(key in this.map_)) {
  68.       return;
  69.     }
  70.     this.map_[key] = this.map_[key].filter((i) => i != value);
  71.   }
  74.   /**
  75.    * Clear all keys and values from the multimap.
  76.    */
  77.   clear() {
  78.     this.map_ = {};
  79.   }
  82.   /**
  83.    * @param {function(string, !Array.<T>)} callback
  84.    */
  85.   forEach(callback) {
  86.     for (const key in this.map_) {
  87.       callback(key, this.map_[key]);
  88.     }
  89.   }
  90. };