blob: f7082608968051740abb83ceb75b7e0fb9b725ce [file] [log] [blame]
/**
* Module exports.
*/
exports.EventEmitter = EventEmitter;
/**
* Check if `obj` is an array.
*/
function isArray(obj) {
return '[object Array]' == {}.toString.call(obj);
}
/**
* Event emitter constructor.
*
* @api public
*/
function EventEmitter(){};
/**
* Adds a listener.
*
* @api public
*/
EventEmitter.prototype.on = function (name, fn) {
if (!this.$events) {
this.$events = {};
}
if (!this.$events[name]) {
this.$events[name] = fn;
} else if (isArray(this.$events[name])) {
this.$events[name].push(fn);
} else {
this.$events[name] = [this.$events[name], fn];
}
return this;
};
EventEmitter.prototype.addListener = EventEmitter.prototype.on;
/**
* Adds a volatile listener.
*
* @api public
*/
EventEmitter.prototype.once = function (name, fn) {
var self = this;
function on () {
self.removeListener(name, on);
fn.apply(this, arguments);
};
on.listener = fn;
this.on(name, on);
return this;
};
/**
* Removes a listener.
*
* @api public
*/
EventEmitter.prototype.removeListener = function (name, fn) {
if (this.$events && this.$events[name]) {
var list = this.$events[name];
if (isArray(list)) {
var pos = -1;
for (var i = 0, l = list.length; i < l; i++) {
if (list[i] === fn || (list[i].listener && list[i].listener === fn)) {
pos = i;
break;
}
}
if (pos < 0) {
return this;
}
list.splice(pos, 1);
if (!list.length) {
delete this.$events[name];
}
} else if (list === fn || (list.listener && list.listener === fn)) {
delete this.$events[name];
}
}
return this;
};
/**
* Removes all listeners for an event.
*
* @api public
*/
EventEmitter.prototype.removeAllListeners = function (name) {
if (name === undefined) {
this.$events = {};
return this;
}
if (this.$events && this.$events[name]) {
this.$events[name] = null;
}
return this;
};
/**
* Gets all listeners for a certain event.
*
* @api public
*/
EventEmitter.prototype.listeners = function (name) {
if (!this.$events) {
this.$events = {};
}
if (!this.$events[name]) {
this.$events[name] = [];
}
if (!isArray(this.$events[name])) {
this.$events[name] = [this.$events[name]];
}
return this.$events[name];
};
/**
* Emits an event.
*
* @api public
*/
EventEmitter.prototype.emit = function (name) {
if (!this.$events) {
return false;
}
var handler = this.$events[name];
if (!handler) {
return false;
}
var args = [].slice.call(arguments, 1);
if ('function' == typeof handler) {
handler.apply(this, args);
} else if (isArray(handler)) {
var listeners = handler.slice();
for (var i = 0, l = listeners.length; i < l; i++) {
listeners[i].apply(this, args);
}
} else {
return false;
}
return true;
};