/*! @license
* Shaka Player
* Copyright 2016 Google LLC
* SPDX-License-Identifier: Apache-2.0
*/
goog.provide('shaka.util.MultiMap');
/**
* @summary A simple multimap template.
* @template T
*/
shaka.util.MultiMap = class {
/** */
constructor() {
/** @private {!Object.<string, !Array.<T>>} */
this.map_ = {};
}
/**
* Add a key, value pair to the map.
* @param {string} key
* @param {T} value
*/
push(key, value) {
if (this.map_.hasOwnProperty(key)) {
this.map_[key].push(value);
} else {
this.map_[key] = [value];
}
}
/**
* Get a list of values by key.
* @param {string} key
* @return {Array.<T>} or null if no such key exists.
*/
get(key) {
const list = this.map_[key];
// slice() clones the list so that it and the map can each be modified
// without affecting the other.
return list ? list.slice() : null;
}
/**
* Get a list of all values.
* @return {!Array.<T>}
*/
getAll() {
const list = [];
for (const key in this.map_) {
list.push(...this.map_[key]);
}
return list;
}
/**
* Remove a specific value, if it exists.
* @param {string} key
* @param {T} value
*/
remove(key, value) {
if (!(key in this.map_)) {
return;
}
this.map_[key] = this.map_[key].filter((i) => i != value);
if (this.map_[key].length == 0) {
// Delete the array if it's empty, so that |get| will reliably return null
// "if no such key exists", instead of sometimes returning an empty array.
delete this.map_[key];
}
}
/**
* Clear all keys and values from the multimap.
*/
clear() {
this.map_ = {};
}
/**
* @param {function(string, !Array.<T>)} callback
*/
forEach(callback) {
for (const key in this.map_) {
callback(key, this.map_[key]);
}
}
/**
* Returns the number of elements in the multimap.
* @return {number}
*/
size() {
return Object.keys(this.map_).length;
}
};