https://noman-ai.jp/assets/lib0--observable-537cdee3.js

1/**
2 * Observable class prototype.
3 *
4 * @module observable
5 */
6
7import * as map from 'lib0/map'
8import * as set from 'lib0/set'
9import * as array from 'lib0/array'
10
11/**
12 * Handles named events.
13 * @experimental
14 *
15 * This is basically a (better typed) duplicate of Observable, which will replace Observable in the
16 * next release.
17 *
18 * @template {{[key in keyof EVENTS]: function(...any):void}} EVENTS
19 */
20export class ObservableV2 {
21  constructor () {
22    /**
23     * Some desc.
24     * @type {Map<string, Set<any>>}
25     */
26    this._observers = map.create()
27  }
28
29  /**
30   * @template {keyof EVENTS & string} NAME
31   * @param {NAME} name
32   * @param {EVENTS[NAME]} f
33   */
34  on (name, f) {
35    map.setIfUndefined(this._observers, /** @type {string} */ (name), set.create).add(f)
36    return f
37  }
38
39  /**
40   * @template {keyof EVENTS & string} NAME
41   * @param {NAME} name
42   * @param {EVENTS[NAME]} f
43   */
44  once (name, f) {
45    /**
46     * @param  {...any} args
47     */
48    const _f = (...args) => {
49      this.off(name, /** @type {any} */ (_f))
50      f(...args)
51    }
52    this.on(name, /** @type {any} */ (_f))
53  }
54
55  /**
56   * @template {keyof EVENTS & string} NAME
57   * @param {NAME} name
58   * @param {EVENTS[NAME]} f
59   */
60  off (name, f) {
61    const observers = this._observers.get(name)
62    if (observers !== undefined) {
63      observers.delete(f)
64      if (observers.size === 0) {
65        this._observers.delete(name)
66      }
67    }
68  }
69
70  /**
71   * Emit a named event. All registered event listeners that listen to the
72   * specified name will receive the event.
73   *
74   * @todo This should catch exceptions
75   *
76   * @template {keyof EVENTS & string} NAME
77   * @param {NAME} name The event name.
78   * @param {Parameters<EVENTS[NAME]>} args The arguments that are applied to the event listener.
79   */
80  emit (name, args) {
81    // copy all listeners to an array first to make sure that no event is emitted to listeners that are subscribed while the event handler is called.
82    return array.from((this._observers.get(name) || map.create()).values()).forEach(f => f(...args))
83  }
84
85  destroy () {
86    this._observers = map.create()
87  }
88}
89
90/* c8 ignore start */
91/**
92 * Handles named events.
93 *
94 * @deprecated
95 * @template N
96 */
97export class Observable {
98  constructor () {
99    /**
100     * Some desc.
101     * @type {Map<N, any>}
102     */
103    this._observers = map.create()
104  }
105
106  /**
107   * @param {N} name
108   * @param {function} f
109   */
110  on (name, f) {
111    map.setIfUndefined(this._observers, name, set.create).add(f)
112  }
113
114  /**
115   * @param {N} name
116   * @param {function} f
117   */
118  once (name, f) {
119    /**
120     * @param  {...any} args
121     */
122    const _f = (...args) => {
123      this.off(name, _f)
124      f(...args)
125    }
126    this.on(name, _f)
127  }
128
129  /**
130   * @param {N} name
131   * @param {function} f
132   */
133  off (name, f) {
134    const observers = this._observers.get(name)
135    if (observers !== undefined) {
136      observers.delete(f)
137      if (observers.size === 0) {
138        this._observers.delete(name)
139      }
140    }
141  }
142
143  /**
144   * Emit a named event. All registered event listeners that listen to the
145   * specified name will receive the event.
146   *
147   * @todo This should catch exceptions
148   *
149   * @param {N} name The event name.
150   * @param {Array<any>} args The arguments that are applied to the event listener.
151   */
152  emit (name, args) {
153    // copy all listeners to an array first to make sure that no event is emitted to listeners that are subscribed while the event handler is called.
154    return array.from((this._observers.get(name) || map.create()).values()).forEach(f => f(...args))
155  }
156
157  destroy () {
158    this._observers = map.create()
159  }
160}
161/* c8 ignore end */