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1 | import { assert } from 'chai'; | |
2 | import { EventEmitter } from './EventEmitter'; | |
3 | ||
4 | describe('EventEmitter', () => { | |
5 | let eventEmitter: EventEmitter; | |
6 | ||
7 | beforeEach(() => { | |
8 | eventEmitter = new EventEmitter(); | |
9 | }); | |
10 | ||
11 | describe('once', () => { | |
12 | it('should trigger the listener only once', () => { | |
13 | let count = 0; | |
14 | const listener = () => count++; | |
15 | eventEmitter.once('test', listener); | |
16 | eventEmitter.emit('test'); | |
17 | assert.equal(count, 1); | |
18 | eventEmitter.emit('test'); | |
19 | assert.equal(count, 1); | |
20 | }); | |
21 | }); | |
22 | ||
23 | describe('emit', () => { | |
24 | it('should emit events to listeners', () => { | |
25 | let count1 = 0; | |
26 | let count2 = 0; | |
27 | const listener1 = () => count1++; | |
28 | const listener2 = () => count2++; | |
29 | eventEmitter.on('test', listener1); | |
30 | eventEmitter.on('test', listener2); | |
31 | eventEmitter.emit('test'); | |
32 | assert.equal(count1, 1); | |
33 | assert.equal(count2, 1); | |
34 | eventEmitter.emit('test'); | |
35 | assert.equal(count1, 2); | |
36 | assert.equal(count2, 2); | |
37 | }); | |
38 | ||
39 | it('should manage multiple listener types', () => { | |
40 | let count1 = 0; | |
41 | let count2 = 0; | |
42 | const listener1 = () => count1++; | |
43 | const listener2 = () => count2++; | |
44 | eventEmitter.on('test', listener1); | |
45 | eventEmitter.on('foo', listener2); | |
46 | eventEmitter.emit('test'); | |
47 | assert.equal(count1, 1); | |
48 | assert.equal(count2, 0); | |
49 | eventEmitter.emit('foo'); | |
50 | assert.equal(count1, 1); | |
51 | assert.equal(count2, 1); | |
52 | }); | |
53 | }); | |
54 | ||
55 | describe('listeners', () => { | |
56 | it('should return listeners for the type requested', () => { | |
57 | assert.equal(eventEmitter.listeners('test').length, 0); | |
58 | const listener = () => {}; | |
59 | eventEmitter.on('test', listener); | |
60 | assert.deepEqual(eventEmitter.listeners('test'), [listener]); | |
61 | }); | |
62 | }); | |
63 | ||
64 | describe('off', () => { | |
65 | it('should remove the specific listener', () => { | |
66 | const listener1 = () => {}; | |
67 | const listener2 = () => {}; | |
68 | eventEmitter.on('foo', listener1); | |
69 | eventEmitter.on('foo', listener2); | |
70 | assert.equal(eventEmitter.listeners('foo').length, 2); | |
71 | eventEmitter.off('foo', listener1); | |
72 | assert.deepEqual(eventEmitter.listeners('foo'), [listener2]); | |
73 | }); | |
74 | }); | |
75 | ||
76 | describe('removeAllListeners', () => { | |
77 | it('should clear all listeners', () => { | |
78 | eventEmitter.on('foo', () => {}); | |
79 | assert.equal(eventEmitter.listeners('foo').length, 1); | |
80 | eventEmitter.removeAllListeners('foo'); | |
81 | assert.equal(eventEmitter.listeners('foo').length, 0); | |
82 | }); | |
83 | }); | |
84 | }); |