node/test/simple/test-event-emitter-remove-listeners.js

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//
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// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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var common = require('../common');
var assert = require('assert');
var events = require('events');

var count = 0;

function listener1() {
  console.log('listener1');
  count++;
}

function listener2() {
  console.log('listener2');
  count++;
}

function listener3() {
  console.log('listener3');
  count++;
}

function remove1() {
  assert(0);
}

function remove2() {
  assert(0);
}

var e1 = new events.EventEmitter();
e1.on('hello', listener1);
e1.on('removeListener', common.mustCall(function(name, cb) {
  assert.equal(name, 'hello');
  assert.equal(cb, listener1);
}));
e1.removeListener('hello', listener1);
assert.deepEqual([], e1.listeners('hello'));

var e2 = new events.EventEmitter();
e2.on('hello', listener1);
e2.on('removeListener', assert.fail);
e2.removeListener('hello', listener2);
assert.deepEqual([listener1], e2.listeners('hello'));

var e3 = new events.EventEmitter();
e3.on('hello', listener1);
e3.on('hello', listener2);
e3.on('removeListener', common.mustCall(function(name, cb) {
  assert.equal(name, 'hello');
  assert.equal(cb, listener1);
}));
e3.removeListener('hello', listener1);
assert.deepEqual([listener2], e3.listeners('hello'));

var e4 = new events.EventEmitter();
e4.on('removeListener', common.mustCall(function(name, cb) {
  if (cb !== remove1) return;
  this.removeListener('quux', remove2);
  this.emit('quux');
}, 2));
e4.on('quux', remove1);
e4.on('quux', remove2);
e4.removeListener('quux', remove1);