RxJS throwlfEmpty

如果源可观察者完成但没有发出值，它将发出 一个错误。 该错误将在那时由可选程序创建 errorFactory参数，否则错误将为 EmptyError。

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

参量

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); }
});