RxJS throwlfEmpty

如果源可觀察者完成但沒有發(fā)出值，它將發(fā)出 一個(gè)錯(cuò)誤。 該錯(cuò)誤將在那時(shí)由可選程序創(chuàng)建 errorFactory參數(shù)，否則錯(cuò)誤將為 EmptyError。

throwIfEmpty<T>(errorFactory: () => any = defaultErrorFactory): MonoTypeOperatorFunction<T>

參量

returns

MonoTypeOperatorFunction<T>

描述

例

import { fromEvent, timer } from 'rxjs';
import { throwIfEmpty, takeUntil } from 'rxjs/operators';
const click$ = fromEvent(document, 'click');
click$.pipe(
  takeUntil(timer(1000)),
  throwIfEmpty(
    () => new Error('the document was not clicked within 1 second')
  ),
)
.subscribe({
  next() { console.log('The button was clicked'); },
  error(err) { console.error(err); }
});