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

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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++;
}

var e1 = new events.EventEmitter();
var e1listeners = e1.listeners('hello');
e1.on('hello', listener1);
assert.equal(e1listeners.length, 1);
e1.removeListener('hello', listener1);
assert.deepEqual([], e1.listeners('hello'));

// identity check, listeners array should be the same
assert.equal(e1listeners, e1.listeners('hello'));

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

var e3 = new events.EventEmitter();
e3.on('hello', listener1);
e3.on('hello', listener2);
var e3listeners = e3.listeners('hello');
assert.equal(e3listeners.length, 2)
e3.removeListener('hello', listener1);
assert.equal(e3listeners.length, 1)
assert.deepEqual([listener2], e3.listeners('hello'));

assert.equal(e3listeners, e3.listeners('hello'));