Angular教程中的管道和水龙头方法是什么? [英] What are pipe and tap methods in Angular tutorial?

问题描述

我正在按照 https://angular.io 上的指南进行操作，但是在查找文档时遇到了麻烦；专门用于方法pipe和tap.我在 https://angular.io 或

I'm following the tutorial at https://angular.io, and I'm having trouble finding documentation; specifically for the methods pipe and tap. I can't find anything on https://angular.io or http://reactivex.io/rxjs/.

我的理解是pipe和tap都是从RxJS导入的Observable的方法，对吗?他们应该怎么办?

My understanding is that pipe and tap are both methods of Observable, which is being imported from RxJS, correct? What are they supposed to do?

这些方法是Angular的一部分吗?这两种方法是做什么的?

Are these methods part of Angular? What do these two methods do?

推荐答案

是的，文档中缺少这些方法.但是，当我深入rxjs存储库时，发现了关于

You are right, the documentation lacks of those methods. However when I dug into rxjs repository, I found nice comments about tap (too long to paste here) and pipe operators:

  /**
   * Used to stitch together functional operators into a chain.
   * @method pipe
   * @return {Observable} the Observable result of all of the operators having
   * been called in the order they were passed in.
   *
   * @example
   *
   * import { map, filter, scan } from 'rxjs/operators';
   *
   * Rx.Observable.interval(1000)
   *   .pipe(
   *     filter(x => x % 2 === 0),
   *     map(x => x + x),
   *     scan((acc, x) => acc + x)
   *   )
   *   .subscribe(x => console.log(x))
   */

简介:

管道:用于将功能操作符缝合在一起.在开始做observable.filter().map().scan()之前，但是由于每个RxJS运算符都是独立的函数，而不是Observable的方法，因此我们需要pipe()来构成这些运算符的链(请参见上面的示例).

In brief:

Pipe: Used to stitch together functional operators into a chain. Before we could just do observable.filter().map().scan(), but since every RxJS operator is a standalone function rather than an Observable's method, we need pipe() to make a chain of those operators (see example above).

点击:可以对观察到的数据产生副作用，但不以任何方式修改.以前称为do().您可以将其视为随时间推移可观察的数组，那么tap()将等效于Array.forEach().

Tap: Can perform side effects with observed data but does not modify the stream in any way. Formerly called do(). You can think of it as if observable was an array over time, then tap() would be an equivalent to Array.forEach().

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