Created
March 2, 2019 13:12
-
-
Save panw3i/8efbbe4cdf5d4fa0c93face2e2a12640 to your computer and use it in GitHub Desktop.
订阅与发布
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| // 两者有啥区别呢？容易看出，用时执行模式，每次在创建一个新的matchEmail2时候，都会新建一个闭包，和创建一个新的 regx | |
| // 立即执行啥时候用呢？ 一般是在封装的遍历在函数引用中都是有同一个时，如果不同情况需要使用多个，那么使用用时执行 | |
| // 很显然，我们如果想要创建一个对象系统的话，需要用用时执行模式 | |
| var Events = function() { | |
| var handlers = {}; | |
| var subscribe = function(type, handler) { | |
| if (!handlers[type]) { | |
| handlers[type] = []; | |
| } | |
| handlers[type].push(handler); | |
| //存储当前这个handler是否被订阅 | |
| var isSubscribed = true; | |
| //每次执行一个订阅函数，返回一个取消订阅回调，只要使用这个函数，那么就取消 | |
| return function unsubscribe() { | |
| if (!isSubscribed) return; //防止多次执行 | |
| isSubscribed = false; | |
| const index = handlers[type].indexOf(handler); | |
| handlers[type].splice(index, 1); | |
| } | |
| } | |
| function dispatch(type) { | |
| if (handlers[type]) { | |
| for (let i = 0; i < handlers[type].length; i++) { | |
| handlers[type][i](); | |
| } | |
| } | |
| } | |
| //闭包对象系统，返回一个对象 | |
| return { | |
| subscribe, | |
| dispatch | |
| } | |
| } | |
| //创建一个event对象 | |
| var event = Events(); | |
| //创建另外一个event对象 | |
| var event1 = Events(); | |
| var unSubscribe = event.subscribe('click', function() {console.log('event click')}); | |
| event1.subscribe('click', function() {console.log('event1 click')}); | |
| event.dispatch('click'); | |
| event1.dispatch('click'); | |
| unSubscribe(); | |
| event.dispatch('click'); |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment