describe('EventEmitter', function tests() {
'use strict';
var EventEmitter = require('./').EventEmitter
, assume = require('assume');
it('inherits when used with require(util).inherits', function () {
function Beast() {
}
require('util').inherits(Beast, EventEmitter);
var moop = new Beast()
, meap = new Beast();
assume(moop).is.instanceOf(Beast);
assume(moop).is.instanceof(EventEmitter);
moop.listeners();
meap.listeners();
moop.on('data', function () {
throw new Error('I should not emit');
});
meap.emit('data', 'rawr');
meap.removeListener('foo');
meap.removeAllListeners();
});
describe('EventEmitter#emit', function () {
it('should return false when there are not events to emit', function () {
var e = new EventEmitter();
assume(e.emit('foo')).equals(false);
assume(e.emit('bar')).equals(false);
});
it('emits with context', function (done) {
var e = new EventEmitter()
, context = 'bar';
e.on('foo', function (bar) {
assume(bar).equals('bar');
assume(this).equals(context);
done();
}, context).emit('foo', 'bar');
});
it('emits with context, multiple arguments (force apply)', function (done) {
var e = new EventEmitter()
, context = 'bar';
e.on('foo', function (bar) {
assume(bar).equals('bar');
assume(this).equals(context);
done();
}, context).emit('foo', 'bar', 1,2,3,4,5,6,7,8,9,0);
});
it('can emit the function with multiple arguments', function () {
var e = new EventEmitter();
for(var i = 0; i < 100; i++) {
(function (j) {
for (var i = 0, args = []; i < j; i++) {
args.push(j);
}
e.once('args', function () {
assume(arguments.length).equals(args.length);
});
e.emit.apply(e, ['args'].concat(args));
})(i);
}
});
it('can emit the function with multiple arguments, multiple listeners', function () {
var e = new EventEmitter();
for(var i = 0; i < 100; i++) {
(function (j) {
for (var i = 0, args = []; i < j; i++) {
args.push(j);
}
e.once('args', function () {
assume(arguments.length).equals(args.length);
});
e.once('args', function () {
assume(arguments.length).equals(args.length);
});
e.once('args', function () {
assume(arguments.length).equals(args.length);
});
e.once('args', function () {
assume(arguments.length).equals(args.length);
});
e.emit.apply(e, ['args'].concat(args));
})(i);
}
});
it('emits with context, multiple listeners (force loop)', function () {
var e = new EventEmitter();
e.on('foo', function (bar) {
assume(bar).equals('bar');
assume(this).equals('bar');
}, 'bar');
e.on('foo', function (bar) {
assume(bar).equals('bar');
assume(this).equals('foo');
}, 'foo');
e.emit('foo', 'bar');
});
it('emits with different contexts', function () {
var e = new EventEmitter()
, pattern = '';
function writer() {
pattern += this;
}
e.on('write', writer, 'foo');
e.on('write', writer, 'baz');
e.once('write', writer, 'bar');
e.once('write', writer, 'banana');
e.emit('write');
assume(pattern).equals('foobazbarbanana');
});
it('should return true when there are events to emit', function (done) {
var e = new EventEmitter();
e.on('foo', function () {
process.nextTick(done);
});
assume(e.emit('foo')).equals(true);
assume(e.emit('foob')).equals(false);
});
it('receives the emitted events', function (done) {
var e = new EventEmitter();
e.on('data', function (a, b, c, d, undef) {
assume(a).equals('foo');
assume(b).equals(e);
assume(c).is.instanceOf(Date);
assume(undef).equals(undefined);
assume(arguments.length).equals(3);
done();
});
e.emit('data', 'foo', e, new Date());
});
it('emits to all event listeners', function () {
var e = new EventEmitter()
, pattern = [];
e.on('foo', function () {
pattern.push('foo1');
});
e.on('foo', function () {
pattern.push('foo2');
});
e.emit('foo');
assume(pattern.join(';')).equals('foo1;foo2');
});
});
describe('EventEmitter#listeners', function () {
it('returns an empty array if no listeners are specified', function () {
var e = new EventEmitter();
assume(e.listeners('foo')).is.a('array');
assume(e.listeners('foo').length).equals(0);
});
it('returns an array of function', function () {
var e = new EventEmitter();
function foo() {}
e.on('foo', foo);
assume(e.listeners('foo')).is.a('array');
assume(e.listeners('foo').length).equals(1);
assume(e.listeners('foo')).deep.equals([foo]);
});
it('is not vulnerable to modifications', function () {
var e = new EventEmitter();
function foo() {}
e.on('foo', foo);
assume(e.listeners('foo')).deep.equals([foo]);
e.listeners('foo').length = 0;
assume(e.listeners('foo')).deep.equals([foo]);
});
});
describe('EventEmitter#once', function () {
it('only emits it once', function () {
var e = new EventEmitter()
, calls = 0;
e.once('foo', function () {
calls++;
});
e.emit('foo');
e.emit('foo');
e.emit('foo');
e.emit('foo');
e.emit('foo');
assume(e.listeners('foo').length).equals(0);
assume(calls).equals(1);
});
it('only emits once if emits are nested inside the listener', function () {
var e = new EventEmitter()
, calls = 0;
e.once('foo', function () {
calls++;
e.emit('foo');
});
e.emit('foo');
assume(e.listeners('foo').length).equals(0);
assume(calls).equals(1);
});
it('only emits once for multiple events', function () {
var e = new EventEmitter()
, multi = 0
, foo = 0
, bar = 0;
e.once('foo', function () {
foo++;
});
e.once('foo', function () {
bar++;
});
e.on('foo', function () {
multi++;
});
e.emit('foo');
e.emit('foo');
e.emit('foo');
e.emit('foo');
e.emit('foo');
assume(e.listeners('foo').length).equals(1);
assume(multi).equals(5);
assume(foo).equals(1);
assume(bar).equals(1);
});
it('only emits once with context', function (done) {
var e = new EventEmitter()
, context = 'foo';
e.once('foo', function (bar) {
assume(this).equals(context);
assume(bar).equals('bar');
done();
}, context).emit('foo', 'bar');
});
});
describe('EventEmitter#removeListener', function () {
it('should only remove the event with the specified function', function () {
var e = new EventEmitter();
function bar() {}
e.on('foo', function () {});
e.on('bar', function () {});
e.on('bar', bar);
assume(e.removeListener('foo', bar)).equals(e);
assume(e.listeners('foo').length).equals(1);
assume(e.listeners('bar').length).equals(2);
assume(e.removeListener('foo')).equals(e);
assume(e.listeners('foo').length).equals(0);
assume(e.listeners('bar').length).equals(2);
assume(e.removeListener('bar', bar)).equals(e);
assume(e.listeners('bar').length).equals(1);
assume(e.removeListener('bar')).equals(e);
assume(e.listeners('bar').length).equals(0);
});
it('should only remove once events when using the once flag', function () {
var e = new EventEmitter();
function foo() {}
e.on('foo', foo);
assume(e.removeListener('foo', function () {}, true)).equals(e);
assume(e.listeners('foo').length).equals(1);
assume(e.removeListener('foo', foo, true)).equals(e);
assume(e.listeners('foo').length).equals(1);
assume(e.removeListener('foo', foo)).equals(e);
assume(e.listeners('foo').length).equals(0);
e.on('foo', foo);
e.once('foo', foo);
assume(e.removeListener('foo', function () {}, true)).equals(e);
assume(e.listeners('foo').length).equals(2);
assume(e.removeListener('foo', foo, true)).equals(e);
assume(e.listeners('foo').length).equals(1);
e.once('foo', foo);
assume(e.removeListener('foo', foo)).equals(e);
assume(e.listeners('foo').length).equals(0);
});
});
describe('EventEmitter#removeAllListeners', function () {
it('removes all events for the specified events', function () {
var e = new EventEmitter();
e.on('foo', function () { throw new Error('oops'); });
e.on('foo', function () { throw new Error('oops'); });
e.on('bar', function () { throw new Error('oops'); });
e.on('aaa', function () { throw new Error('oops'); });
assume(e.removeAllListeners('foo')).equals(e);
assume(e.listeners('foo').length).equals(0);
assume(e.listeners('bar').length).equals(1);
assume(e.listeners('aaa').length).equals(1);
assume(e.removeAllListeners('bar')).equals(e);
assume(e.removeAllListeners('aaa')).equals(e);
assume(e.emit('foo')).equals(false);
assume(e.emit('bar')).equals(false);
assume(e.emit('aaa')).equals(false);
});
it('just nukes the fuck out of everything', function () {
var e = new EventEmitter();
e.on('foo', function () { throw new Error('oops'); });
e.on('foo', function () { throw new Error('oops'); });
e.on('bar', function () { throw new Error('oops'); });
e.on('aaa', function () { throw new Error('oops'); });
assume(e.removeAllListeners()).equals(e);
assume(e.listeners('foo').length).equals(0);
assume(e.listeners('bar').length).equals(0);
assume(e.listeners('aaa').length).equals(0);
assume(e.emit('foo')).equals(false);
assume(e.emit('bar')).equals(false);
assume(e.emit('aaa')).equals(false);
});
});
describe('#setMaxListeners', function () {
it('is a function', function () {
var e = new EventEmitter();
assume(e.setMaxListeners).is.a('function');
});
it('returns self when called', function () {
var e = new EventEmitter();
assume(e.setMaxListeners()).to.equal(e);
});
});
});
