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
// deno-fmt-ignore-file// deno-lint-ignore-file
// Copyright Joyent and Node contributors. All rights reserved. MIT license.// Taken from Node 18.12.0// This file is automatically generated by "node/_tools/setup.ts". Do not modify this file manually
// Copyright Joyent, Inc. and other Node contributors.//// Permission is hereby granted, free of charge, to any person obtaining a// copy of this software and associated documentation files (the// "Software"), to deal in the Software without restriction, including// without limitation the rights to use, copy, modify, merge, publish,// distribute, sublicense, and/or sell copies of the Software, and to permit// persons to whom the Software is furnished to do so, subject to the// following conditions://// The above copyright notice and this permission notice shall be included// in all copies or substantial portions of the Software.//// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE// USE OR OTHER DEALINGS IN THE SOFTWARE.
'use strict';const common = require('../common');const assert = require('assert');const EventEmitter = require('events');
{  const ee = new EventEmitter();  const events_new_listener_emitted = [];  const listeners_new_listener_emitted = [];
  // Sanity check  assert.strictEqual(ee.addListener, ee.on);
  ee.on('newListener', function(event, listener) {    // Don't track newListener listeners.    if (event === 'newListener')      return;
    events_new_listener_emitted.push(event);    listeners_new_listener_emitted.push(listener);  });
  const hello = common.mustCall(function(a, b) {    assert.strictEqual(a, 'a');    assert.strictEqual(b, 'b');  });
  ee.once('newListener', function(name, listener) {    assert.strictEqual(name, 'hello');    assert.strictEqual(listener, hello);    assert.deepStrictEqual(this.listeners('hello'), []);  });
  ee.on('hello', hello);  ee.once('foo', assert.fail);  assert.deepStrictEqual(['hello', 'foo'], events_new_listener_emitted);  assert.deepStrictEqual([hello, assert.fail], listeners_new_listener_emitted);
  ee.emit('hello', 'a', 'b');}
// Just make sure that this doesn't throw:{  const f = new EventEmitter();
  f.setMaxListeners(0);}
{  const listen1 = () => {};  const listen2 = () => {};  const ee = new EventEmitter();
  ee.once('newListener', function() {    assert.deepStrictEqual(ee.listeners('hello'), []);    ee.once('newListener', function() {      assert.deepStrictEqual(ee.listeners('hello'), []);    });    ee.on('hello', listen2);  });  ee.on('hello', listen1);  // The order of listeners on an event is not always the order in which the  // listeners were added.  assert.deepStrictEqual(ee.listeners('hello'), [listen2, listen1]);}