rxjs中的Observable和Subject之间有什么区别? [英] What is the difference between Observable and a Subject in rxjs?

问题描述

我正在浏览博客并阅读有关Observable的内容，但无法理解找出可观察对象和主题之间的区别.

I was going through this blog and reading about Observables and couldn't figure out the difference between the Observable and a Subject.

推荐答案

在流编程中，有两个主要接口:可观察和观察者.

In stream programming there are two main interfaces: Observable and Observer.

可观察供消费者使用，可以进行转换和订阅:

Observable is for the consumer, it can be transformed and subscribed:

observable.map(x => ...).filter(x => ...).subscribe(x => ...)

观察者是用于提供可观察源的界面:

Observer is the interface which is used to feed an observable source:

observer.next(newItem)

我们可以使用观察者创建新的可观察:

We can create new Observable with an Observer:

var observable = Observable.create(observer => { 
    observer.next('first'); 
    observer.next('second'); 
    ... 
});
observable.map(x => ...).filter(x => ...).subscribe(x => ...)

或者，我们可以使用 Subject 来实现 Observable 和 Observer 接口:

Or, we can use a Subject which implements both the Observable and the Observer interfaces:

var source = new Subject();
source.map(x => ...).filter(x => ...).subscribe(x => ...)
source.next('first')
source.next('second')

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