define(function () { /** * Event listener (singleton) */ // TODO: replace usage of the event listener for the EventBus var events = { ‘listeners‘: [], /** * Find a single listener by its object * @param {Object} object * @return {Number} index -1 when not found */ ‘indexOf‘: function (object) { var listeners = this.listeners; for (var i = 0, iMax = this.listeners.length; i < iMax; i++) { var listener = listeners[i]; if (listener && listener.object == object) { return i; } } return -1; }, /** * Add an event listener * @param {Object} object * @param {String} event The name of an event, for example ‘select‘ * @param {function} callback The callback method, called when the * event takes place */ ‘addListener‘: function (object, event, callback) { var index = this.indexOf(object); var listener = this.listeners[index]; if (!listener) { listener = { ‘object‘: object, ‘events‘: {} }; this.listeners.push(listener); } var callbacks = listener.events[event]; if (!callbacks) { callbacks = []; listener.events[event] = callbacks; } // add the callback if it does not yet exist if (callbacks.indexOf(callback) == -1) { callbacks.push(callback); } }, /** * Remove an event listener * @param {Object} object * @param {String} event The name of an event, for example ‘select‘ * @param {function} callback The registered callback method */ ‘removeListener‘: function (object, event, callback) { var index = this.indexOf(object); var listener = this.listeners[index]; if (listener) { var callbacks = listener.events[event]; if (callbacks) { index = callbacks.indexOf(callback); if (index != -1) { callbacks.splice(index, 1); } // remove the array when empty if (callbacks.length == 0) { delete listener.events[event]; } } // count the number of registered events. remove listener when empty var count = 0; var events = listener.events; for (var e in events) { if (events.hasOwnProperty(e)) { count++; } } if (count == 0) { delete this.listeners[index]; } } }, /** * Remove all registered event listeners */ ‘removeAllListeners‘: function () { this.listeners = []; }, /** * Trigger an event. All registered event handlers will be called * @param {Object} object * @param {String} event * @param {Object} properties (optional) */ ‘trigger‘: function (object, event, properties) { var index = this.indexOf(object); var listener = this.listeners[index]; if (listener) { var callbacks = listener.events[event]; if (callbacks) { for (var i = 0, iMax = callbacks.length; i < iMax; i++) { callbacks[i](properties); } } } } }; return events; });
以上是来自visjs的自定义事件模块,不知道为什么他们自己放着没用,看了一下非常实用,所以就直接拿过来用就可以。
时间: 2024-10-23 22:22:32