javascript的事件触发和接收源码
define(function(require,exports,module){ var Events=function(){ var array = []; var push = array.push; var slice = array.slice; var splice = array.splice; var Events = { // Bind an event to a `callback` function. Passing `"all"` will bind // the callback to all events fired. on: function(name, callback, context) { if (!eventsApi(this, 'on', name, [callback, context]) || !callback) return this; this._events || (this._events = {}); var events = this._events[name] || (this._events[name] = []); events.push({callback: callback, context: context, ctx: context || this}); return this; }, // Bind an event to only be triggered a single time. After the first time // the callback is invoked, it will be removed. once: function(name, callback, context) { if (!eventsApi(this, 'once', name, [callback, context]) || !callback) return this; var self = this; var once = _.once(function() { self.off(name, once); callback.apply(this, arguments); }); once._callback = callback; return this.on(name, once, context); }, // Remove one or many callbacks. If `context` is null, removes all // callbacks with that function. If `callback` is null, removes all // callbacks for the event. If `name` is null, removes all bound // callbacks for all events. off: function(name, callback, context) { var retain, ev, events, names, i, l, j, k; if (!this._events || !eventsApi(this, 'off', name, [callback, context])) return this; if (!name && !callback && !context) { this._events = {}; return this; } names = name ? [name] : _.keys(this._events); for (i = 0, l = names.length; i < l; i++) { name = names[i]; if (events = this._events[name]) { this._events[name] = retain = []; if (callback || context) { for (j = 0, k = events.length; j < k; j++) { ev = events[j]; if ((callback && callback !== ev.callback && callback !== ev.callback._callback) || (context && context !== ev.context)) { retain.push(ev); } } } if (!retain.length) delete this._events[name]; } } return this; }, // Trigger one or many events, firing all bound callbacks. Callbacks are // passed the same arguments as `trigger` is, apart from the event name // (unless you're listening on `"all"`, which will cause your callback to // receive the true name of the event as the first argument). trigger: function(name) { if (!this._events) return this; var args = slice.call(arguments, 1); if (!eventsApi(this, 'trigger', name, args)) return this; var events = this._events[name]; var allEvents = this._events.all; if (events) triggerEvents(events, args); if (allEvents) triggerEvents(allEvents, arguments); return this; }, // Tell this object to stop listening to either specific events ... or // to every object it's currently listening to. stopListening: function(obj, name, callback) { var listeners = this._listeners; if (!listeners) return this; var deleteListener = !name && !callback; if (typeof name === 'object') callback = this; if (obj) (listeners = {})[obj._listenerId] = obj; for (var id in listeners) { listeners[id].off(name, callback, this); if (deleteListener) delete this._listeners[id]; } return this; } }; // Regular expression used to split event strings. var eventSplitter = /\s+/; // Implement fancy features of the Events API such as multiple event // names `"change blur"` and jQuery-style event maps `{change: action}` // in terms of the existing API. var eventsApi = function(obj, action, name, rest) { if (!name) return true; // Handle event maps. if (typeof name === 'object') { for (var key in name) { obj[action].apply(obj, [key, name[key]].concat(rest)); } return false; } // Handle space separated event names. if (eventSplitter.test(name)) { var names = name.split(eventSplitter); for (var i = 0, l = names.length; i < l; i++) { obj[action].apply(obj, [names[i]].concat(rest)); } return false; } return true; }; // A difficult-to-believe, but optimized internal dispatch function for // triggering events. Tries to keep the usual cases speedy (most internal // Backbone events have 3 arguments). var triggerEvents = function(events, args) { var ev, i = -1, l = events.length, a1 = args[0], a2 = args[1], a3 = args[2]; switch (args.length) { case 0: while (++i < l) (ev = events[i]).callback.call(ev.ctx); return; case 1: while (++i < l) (ev = events[i]).callback.call(ev.ctx, a1); return; case 2: while (++i < l) (ev = events[i]).callback.call(ev.ctx, a1, a2); return; case 3: while (++i < l) (ev = events[i]).callback.call(ev.ctx, a1, a2, a3); return; default: while (++i < l) (ev = events[i]).callback.apply(ev.ctx, args); } }; // Aliases for backwards compatibility. Events.bind = Events.on; Events.unbind = Events.off; return Events; }() module.exports=Events })