1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
// deno-fmt-ignore-file// deno-lint-ignore-file
// Copyright Joyent and Node contributors. All rights reserved. MIT license.// Taken from Node 18.8.0// This file is automatically generated by "node/_tools/setup.ts". Do not modify this file manually
// TODO(cjihrig): kEvents is an internally used symbol in Node.js. It is not// implemented in Deno, so parts of this test must be removed in order to pass.
'use strict';// Flags: --no-warnings
const common = require('../common');const { once, EventEmitter } = require('events');const {  strictEqual,  deepStrictEqual,  fail,  rejects,} = require('assert');
async function onceAnEvent() {  const ee = new EventEmitter();
  process.nextTick(() => {    ee.emit('myevent', 42);  });
  const [value] = await once(ee, 'myevent');  strictEqual(value, 42);  strictEqual(ee.listenerCount('error'), 0);  strictEqual(ee.listenerCount('myevent'), 0);}
async function onceAnEventWithNullOptions() {  const ee = new EventEmitter();
  process.nextTick(() => {    ee.emit('myevent', 42);  });
  const [value] = await once(ee, 'myevent', null);  strictEqual(value, 42);}

async function onceAnEventWithTwoArgs() {  const ee = new EventEmitter();
  process.nextTick(() => {    ee.emit('myevent', 42, 24);  });
  const value = await once(ee, 'myevent');  deepStrictEqual(value, [42, 24]);}
async function catchesErrors() {  const ee = new EventEmitter();
  const expected = new Error('kaboom');  let err;  process.nextTick(() => {    ee.emit('error', expected);  });
  try {    await once(ee, 'myevent');  } catch (_e) {    err = _e;  }  strictEqual(err, expected);  strictEqual(ee.listenerCount('error'), 0);  strictEqual(ee.listenerCount('myevent'), 0);}
async function catchesErrorsWithAbortSignal() {  const ee = new EventEmitter();  const ac = new AbortController();  const signal = ac.signal;
  const expected = new Error('boom');  let err;  process.nextTick(() => {    ee.emit('error', expected);  });
  try {    const promise = once(ee, 'myevent', { signal });    strictEqual(ee.listenerCount('error'), 1);
    await promise;  } catch (e) {    err = e;  }  strictEqual(err, expected);  strictEqual(ee.listenerCount('error'), 0);  strictEqual(ee.listenerCount('myevent'), 0);}
async function stopListeningAfterCatchingError() {  const ee = new EventEmitter();
  const expected = new Error('kaboom');  let err;  process.nextTick(() => {    ee.emit('error', expected);    ee.emit('myevent', 42, 24);  });
  try {    await once(ee, 'myevent');  } catch (_e) {    err = _e;  }  process.removeAllListeners('multipleResolves');  strictEqual(err, expected);  strictEqual(ee.listenerCount('error'), 0);  strictEqual(ee.listenerCount('myevent'), 0);}
async function onceError() {  const ee = new EventEmitter();
  const expected = new Error('kaboom');  process.nextTick(() => {    ee.emit('error', expected);  });
  const promise = once(ee, 'error');  strictEqual(ee.listenerCount('error'), 1);  const [ err ] = await promise;  strictEqual(err, expected);  strictEqual(ee.listenerCount('error'), 0);  strictEqual(ee.listenerCount('myevent'), 0);}
async function onceWithEventTarget() {  const et = new EventTarget();  const event = new Event('myevent');  process.nextTick(() => {    et.dispatchEvent(event);  });  const [ value ] = await once(et, 'myevent');  strictEqual(value, event);}
async function onceWithEventTargetError() {  const et = new EventTarget();  const error = new Event('error');  process.nextTick(() => {    et.dispatchEvent(error);  });
  const [ err ] = await once(et, 'error');  strictEqual(err, error);}
async function prioritizesEventEmitter() {  const ee = new EventEmitter();  ee.addEventListener = fail;  ee.removeAllListeners = fail;  process.nextTick(() => ee.emit('foo'));  await once(ee, 'foo');}
async function abortSignalBefore() {  const ee = new EventEmitter();  ee.on('error', common.mustNotCall());  const abortedSignal = AbortSignal.abort();
  await Promise.all([1, {}, 'hi', null, false].map((signal) => {    return rejects(once(ee, 'foo', { signal }), {      code: 'ERR_INVALID_ARG_TYPE'    });  }));
  return rejects(once(ee, 'foo', { signal: abortedSignal }), {    name: 'AbortError'  });}
async function abortSignalAfter() {  const ee = new EventEmitter();  const ac = new AbortController();  ee.on('error', common.mustNotCall());  const r = rejects(once(ee, 'foo', { signal: ac.signal }), {    name: 'AbortError'  });  process.nextTick(() => ac.abort());  return r;}
async function abortSignalAfterEvent() {  const ee = new EventEmitter();  const ac = new AbortController();  process.nextTick(() => {    ee.emit('foo');    ac.abort();  });  const promise = once(ee, 'foo', { signal: ac.signal });  await promise;}
async function abortSignalRemoveListener() {  const ee = new EventEmitter();  const ac = new AbortController();
  try {    process.nextTick(() => ac.abort());    await once(ee, 'test', { signal: ac.signal });  } catch {    strictEqual(ee.listeners('test').length, 0);    strictEqual(ee.listeners('error').length, 0);  }}
async function eventTargetAbortSignalBefore() {  const et = new EventTarget();  const abortedSignal = AbortSignal.abort();
  await Promise.all([1, {}, 'hi', null, false].map((signal) => {    return rejects(once(et, 'foo', { signal }), {      code: 'ERR_INVALID_ARG_TYPE'    });  }));
  return rejects(once(et, 'foo', { signal: abortedSignal }), {    name: 'AbortError'  });}
async function eventTargetAbortSignalAfter() {  const et = new EventTarget();  const ac = new AbortController();  const r = rejects(once(et, 'foo', { signal: ac.signal }), {    name: 'AbortError'  });  process.nextTick(() => ac.abort());  return r;}
async function eventTargetAbortSignalAfterEvent() {  const et = new EventTarget();  const ac = new AbortController();  process.nextTick(() => {    et.dispatchEvent(new Event('foo'));    ac.abort();  });  await once(et, 'foo', { signal: ac.signal });}
Promise.all([  onceAnEvent(),  onceAnEventWithNullOptions(),  onceAnEventWithTwoArgs(),  catchesErrors(),  catchesErrorsWithAbortSignal(),  stopListeningAfterCatchingError(),  onceError(),  onceWithEventTarget(),  onceWithEventTargetError(),  prioritizesEventEmitter(),  abortSignalBefore(),  abortSignalAfter(),  abortSignalAfterEvent(),  abortSignalRemoveListener(),  eventTargetAbortSignalBefore(),  eventTargetAbortSignalAfter(),  eventTargetAbortSignalAfterEvent(),]).then(common.mustCall());