RxJS中的map vs switchMap [英] map vs switchMap in RxJS

问题描述

我阅读了 switchMap 和

I read the documentation of switchMap and map, but I still don't completely understand the difference. Are there some cases where it does not make a difference at all?

推荐答案

两个运算符都不同.

switchMap :将值映射为可观察值.取消先前的内部可观测值.

switchMap: Maps values to observable. Cancels the previous inner observable.

例如:

fromEvent(document, 'click')
  .pipe(
    // restart counter on every click
    // First click: 0, 1, 2...
    // Second click: cancels the previous interval and starts new one. 0, 1, 2...
    switchMap(() => interval(1000))
  )
  .subscribe(console.log);

地图:为每个值添加投影.

map: Add projection with each value.

例如:

//add 10 to each value
const example = source.pipe(map(val => val + 10));

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