RxJS Subjects

Subjects could be both an Observable and an Observer. They can be seen as a pushable Observable; they let you add more data to be propagated through them.

Subjects expose three important methods: onNext(), onError(), and onCompleted(). These methods can be used to send events through the observable sequence. You can see their usage in the following example:

var subject = new Rx.Subject(); subject.subscribe(     (message)=> console.log(message),     (err)=>console.log('An error happened: '+err.message),     ()=>console.log('END') ); subject.onNext('Hello World!!!'); subject.onCompleted(); 

In this example, we created a new subject and subscribed to it, using the subscribe() method. Then, we pushed data on this subject using the onNext() ...

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