176 lines
3.3 KiB
JavaScript
176 lines
3.3 KiB
JavaScript
|
|
/**
|
|
* Expose `Emitter`.
|
|
*/
|
|
|
|
exports.Emitter = Emitter;
|
|
|
|
/**
|
|
* Initialize a new `Emitter`.
|
|
*
|
|
* @api public
|
|
*/
|
|
|
|
function Emitter(obj) {
|
|
if (obj) return mixin(obj);
|
|
}
|
|
|
|
/**
|
|
* Mixin the emitter properties.
|
|
*
|
|
* @param {Object} obj
|
|
* @return {Object}
|
|
* @api private
|
|
*/
|
|
|
|
function mixin(obj) {
|
|
for (var key in Emitter.prototype) {
|
|
obj[key] = Emitter.prototype[key];
|
|
}
|
|
return obj;
|
|
}
|
|
|
|
/**
|
|
* Listen on the given `event` with `fn`.
|
|
*
|
|
* @param {String} event
|
|
* @param {Function} fn
|
|
* @return {Emitter}
|
|
* @api public
|
|
*/
|
|
|
|
Emitter.prototype.on =
|
|
Emitter.prototype.addEventListener = function(event, fn){
|
|
this._callbacks = this._callbacks || {};
|
|
(this._callbacks['$' + event] = this._callbacks['$' + event] || [])
|
|
.push(fn);
|
|
return this;
|
|
};
|
|
|
|
/**
|
|
* Adds an `event` listener that will be invoked a single
|
|
* time then automatically removed.
|
|
*
|
|
* @param {String} event
|
|
* @param {Function} fn
|
|
* @return {Emitter}
|
|
* @api public
|
|
*/
|
|
|
|
Emitter.prototype.once = function(event, fn){
|
|
function on() {
|
|
this.off(event, on);
|
|
fn.apply(this, arguments);
|
|
}
|
|
|
|
on.fn = fn;
|
|
this.on(event, on);
|
|
return this;
|
|
};
|
|
|
|
/**
|
|
* Remove the given callback for `event` or all
|
|
* registered callbacks.
|
|
*
|
|
* @param {String} event
|
|
* @param {Function} fn
|
|
* @return {Emitter}
|
|
* @api public
|
|
*/
|
|
|
|
Emitter.prototype.off =
|
|
Emitter.prototype.removeListener =
|
|
Emitter.prototype.removeAllListeners =
|
|
Emitter.prototype.removeEventListener = function(event, fn){
|
|
this._callbacks = this._callbacks || {};
|
|
|
|
// all
|
|
if (0 == arguments.length) {
|
|
this._callbacks = {};
|
|
return this;
|
|
}
|
|
|
|
// specific event
|
|
var callbacks = this._callbacks['$' + event];
|
|
if (!callbacks) return this;
|
|
|
|
// remove all handlers
|
|
if (1 == arguments.length) {
|
|
delete this._callbacks['$' + event];
|
|
return this;
|
|
}
|
|
|
|
// remove specific handler
|
|
var cb;
|
|
for (var i = 0; i < callbacks.length; i++) {
|
|
cb = callbacks[i];
|
|
if (cb === fn || cb.fn === fn) {
|
|
callbacks.splice(i, 1);
|
|
break;
|
|
}
|
|
}
|
|
|
|
// Remove event specific arrays for event types that no
|
|
// one is subscribed for to avoid memory leak.
|
|
if (callbacks.length === 0) {
|
|
delete this._callbacks['$' + event];
|
|
}
|
|
|
|
return this;
|
|
};
|
|
|
|
/**
|
|
* Emit `event` with the given args.
|
|
*
|
|
* @param {String} event
|
|
* @param {Mixed} ...
|
|
* @return {Emitter}
|
|
*/
|
|
|
|
Emitter.prototype.emit = function(event){
|
|
this._callbacks = this._callbacks || {};
|
|
|
|
var args = new Array(arguments.length - 1)
|
|
, callbacks = this._callbacks['$' + event];
|
|
|
|
for (var i = 1; i < arguments.length; i++) {
|
|
args[i - 1] = arguments[i];
|
|
}
|
|
|
|
if (callbacks) {
|
|
callbacks = callbacks.slice(0);
|
|
for (var i = 0, len = callbacks.length; i < len; ++i) {
|
|
callbacks[i].apply(this, args);
|
|
}
|
|
}
|
|
|
|
return this;
|
|
};
|
|
|
|
// alias used for reserved events (protected method)
|
|
Emitter.prototype.emitReserved = Emitter.prototype.emit;
|
|
|
|
/**
|
|
* Return array of callbacks for `event`.
|
|
*
|
|
* @param {String} event
|
|
* @return {Array}
|
|
* @api public
|
|
*/
|
|
|
|
Emitter.prototype.listeners = function(event){
|
|
this._callbacks = this._callbacks || {};
|
|
return this._callbacks['$' + event] || [];
|
|
};
|
|
|
|
/**
|
|
* Check if this emitter has `event` handlers.
|
|
*
|
|
* @param {String} event
|
|
* @return {Boolean}
|
|
* @api public
|
|
*/
|
|
|
|
Emitter.prototype.hasListeners = function(event){
|
|
return !! this.listeners(event).length;
|
|
};
|