[RxJS] Returning subscriptions from the subscribe function

最新推荐文章于 2020-10-12 20:58:04 发布

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最新推荐文章于 2020-10-12 20:58:04 发布

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原文链接：http://www.cnblogs.com/Answer1215/p/5402838.html

本文介绍如何在RxJS中创建可观察对象，并允许观察者进行订阅和取消订阅操作。通过示例展示了如何使用setInterval生成定时消息并利用clearInterval来停止发送消息。

So far, when writing these subscribe functions, we haven't returned anything. It is possible return an unsubscribe function from a subscribe function. In this lesson we will see how to allow observers to subscribe and unsubscribe from an Observable.

var foo = new Rx.Observable(function subscribe(observer) {
  var id = setInterval(function () {
    observer.next('hi');
  }, 1000);
  return function unsubscribe() {
    clearInterval(id);
  };
});

var subscription = foo.subscribe({
  next: function (x) { console.log('next ' + x); },
  error: function (err) { console.log('error ' + err); },
  complete: function () { console.log('done'); },
});

setTimeout(function () {
  subscription.unsubscribe();  
}, 4500);