以下是我使用的HTML代码段作为示例：
<html>
<head>
<script src="rx.all.js"></script>
</head>
<body>
<script>
var source = new Rx.BehaviorSubject(function() {return 2;});
var stuff = source.scan([], function(val, operation) {
return operation(val);
});
stuff.subscribe(function(v) {
console.log("first subscriber");
console.log(v);
});
source.onNext(function(val) {
return val * 2;
});
stuff.subscribe(function(v) {
console.log("second subscriber");
console.log(v);
});
</script>
</body>
JS控制台中的输出是：
first subscriber
2
first subscriber
4
second subscriber
0
现在,“stuff”进行了一些处理(基本上将函数应用于当前值),这是我从TodoMVC示例中获取的ReactJs RxJS(https://github.com/fdecampredon/react-rxjs-todomvc)的想法.
我想要实现的输出是让第二个用户在订阅时也看到“4”.我正在将RxJS与ReactJS结合使用,因此组件在卸载时会取消订阅(由于路由更改),并在再次安装时再次订阅.
解决方法:
使用replay(1)将你的东西变成一个热门观察者,它将记住最后一个值并将其提供给后来者：
var stuff = ...;
stuff = stuff.replay(1);
// go ahead and start it listening
// you could use .refCount() here also
var subscription = stuff.connect();
// now subscribe your observers
stuff.subscribe(...);
// send some results
source.onNext(...);
source.onNext(...);
// subscribe another observer
// will see the lastest value
// as well as any new values
stuff.subscribe(...);
source.onNext(...);
// ...