JS实现观察者模式

1             //观察者模式  又称订阅发布模式
2             function Newspaper() {
3                 var list = new Set();
4                 //订阅
5                 this.subscribe = function(c) {
6                     list.add(c);
7                 }
8                 //取消订阅
9                 this.unsubscribe = function(c) {
10                     list.remove();
11                 }
12                 //发布新闻
13                 this.publish = function(msg) {
14                     for(var i of list.keys()) {
15                         i.notice(msg);
16                     }
17                 }
18                 //每4s产生一条新闻
19                 this.start = function() {
20                     setInterval(function() {
21                         this.publish(Math.random());
22                     }.bind(this), 4000);
23                 }
24             }
25
26             function Client() {
27                 this.notice = function(msg) {
28                     console.log(this.type + "内容：" + msg);
29                 }
30             }
31             var QQ = function() {
32                 this.type = "QQ";
33             };
34             QQ.prototype = new Client();
35             var Email = function() {
36                 this.type = "Email";
37             };
38             Email.prototype = new Client();
39
40             var theme = new Newspaper();
41             theme.start();
42             theme.subscribe(new QQ("aaa"));
43             theme.subscribe(new Email("aaa@qq.com"));