jQuery事件高级应用EventListener/EventHandler（一）

概述

在Web前端开发中，我们经常会遇到以下需求：在渲染一个页面前需要执行function1, function2,function3... 在渲染页面后需要执行function4, function5, function6...在将后台数据绑定到页面前要执行function7, function8...在数据绑定到页面后要执行function9, function10...

主要代码如下

var EventListener = function () {};
EventListener.prototype = {
  ns: 'co',
  event: {},
  handlerPool: {},
  widget: function () {
    return $(document);
  },
  trigger: function (type, data) {
    if (!this.accept(type)) {
      return false;
    }
    this.__bindHandlers(type);

    var e = $.Event(type + '.' + this.ns);
    e.options = data;
    return this.widget().trigger(e);
  },
  register: function (type, handler) {
    if (!this.accept(type) || !handler) {
      return false;
    }

    if ($.isFunction(handler)) {
      handler = $.extend(new EventHandler(), {
        handle: handler
      });
    }

    var eventType = type;
    var handlers = this.handlerPool[eventType] || [];
    handlers.push(handler);
    this.handlerPool[eventType] = handlers;
  },
  unregister: function (type, handler) {
    if (!this.accept(type)) {
      return false;
    }

    var handlers = this.handlerPool[type];
    if (handler && handlers) {
      var leftHandlers = $.grep(handlers, function (obj) {
        return obj.handle !== handler;
      });
      if (leftHandlers.length && leftHandlers.length < handlers.length) {
        this.handlerPool[type] = leftHandlers;
      }
      return;
    }

    delete this.handlerPool[type];
  },
  accept: function (type) {
    var accepted = false;

    $.each(this.event, function (key, name) {
      if (name === type) {
        accepted = true;
        return false;
      }
    });
    return accepted;
  },
  __bindHandlers: function (type) {
    var self = this;

    if (type) {
      self.widget().unbind(type + '.' + this.ns);

      var handlers = this.handlerPool[type] || [];
      $.each(handlers, function (i, handler) {
        self.widget().bind(type + '.' + self.ns, handler.data || {}, handler.handle);
      });
    }
  }
};

var EventHandler = function () {};

EventHandler.prototype.__type = 'EventHandler';

EventHandler.prototype.handle = function () {
  return this;
};

具体如何使用，下次再将吧...