RxJS - 从 EventEmitter 的多个事件创建 Observable [英] RxJS - Create Observable from an EventEmitter's multiple events

问题描述

我有一个 node.js EventEmitter，它引发以下事件:error、message.

I have a node.js EventEmitter which raises the following events: error, message.

是否有一种直接的方法可以从中创建 RxJS Observable?

Is there a straight forward way I can create an RxJS Observable from it?

i.e next() 调用 message 和 error() 调用 error.

i.e next() called on message and error() called on error.

推荐答案

你可以这样创建:

const obs$ = Observable.create(observer => {
  emitter.on('message', val => observer.next(val));
  emitter.on('error', err => observer.error(err));
});

<小时>

作为替代方案，您可以通过像这样构造和链接 observables 来实现此目的，但显然可读性较差:

---

As an alternative, you can do this by constructinng and chaining observables like this, but it's clearly less readable:

const message$ = Observable.fromEvent(emitter, 'message');
const error$ = Observable.fromEvent(emitter, 'error');

const obs$ = Observable.merge(
  message$.catch(err => Observable.of(err)),
  error$.mergeMap(val => Observable.throw(val)),
);

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