javascript - RxJS skipWhile 与过滤器

Question

skipWhile 和过滤运算符有什么区别？

const source = interval(1000);
const example = source.pipe(skipWhile(val => val < 5));
const subscribe = example.subscribe(val => console.log(val));


const source = interval(1000);
const example = source.pipe(filter(val => val > 5));
const subscribe = example.subscribe(val => console.log(val));

Answer 1

不同之处在于，在其表达式评估为 false 时，skipWhile 切换到镜像其源可观察对象 - 因此它将停止过滤掉任何进一步的值。

例如:

Observable.from([1,2,3,4,5])
  .pipe(filter(val => val % 2 == 0)) // filters out odd numbers
  .subscribe(val => console.log(val)); // emits 2,4

Observable.from([1,2,3,4,5])
  .pipe(skipWhile(val => val % 2 == 1)) // filters odd numbers until an even number comes along
  .subscribe(val => console.log(val)); // emits 2,3,4,5