delayWhen
延迟投射值,延迟时间由提供函数决定。
用法
delayWhen<T>(
delayDurationSelector: (value: T, index: number) => Observable<any>,
subscriptionDelay?: Observable<any>
): MonoTypeOperatorFunction<T>
参数
参数 | 说明 |
---|---|
delayDurationSelector | 延迟选择器。 |
subscriptionDelay | 可选。默认值:undefined 。触发订阅。 |
返回
类型: MonoTypeOperatorFunction<T>
示例
import { interval, timer } from 'rxjs';
import { delayWhen } from 'rxjs/operators';
// 每1秒投射值
const message = interval(1000);
// 5秒后投射值
const delayForFiveSeconds = () => timer(5000);
// 5秒后,开始投射 interval 延迟的值
const delayWhenExample = message.pipe(delayWhen(delayForFiveSeconds));
// 延迟5秒后输出值
// 例如, 输出: 0...1...2...3
const subscribe = delayWhenExample.subscribe(val => console.log(val));
源码
https://github.com/ReactiveX/rxjs/blob/master/src/internal/operators/delayWhen.ts