// RxJS v6+
import { mapTo } from 'rxjs/operators';
import { interval } from 'rxjs/observable/interval';
import { race } from 'rxjs/observable/race';
// 接收第一个发出值的 observable
const example = race(
  // 每1.5秒发出值
  interval(1500),
  // 每1秒发出值
  interval(1000).pipe(mapTo('1s won!')),
  // 每2秒发出值
  interval(2000),
  // 每2.5秒发出值
  interval(2500)
// 输出: "1s won!"..."1s won!"...etc
const subscribe = example.subscribe(val => console.log(val));
示例 2: 使用 error 进行 race
StackBlitz
| jsFiddle )

// RxJS v6+
import { delay, map } from 'rxjs/operators';
import { of, race } from 'rxjs';
// 抛出错误并忽略其他的 observables 。
const first = of('first').pipe(
  delay(100),
  map(_ => {
    throw 'error';
const second = of('second').pipe(delay(200));
const third = of('third').pipe(delay(300));
// nothing logged
race(first, second, third).subscribe(val => console.log(val));
race  - 官方文档
 源码:  https://github.com/ReactiveX/rxjs/blob/master/src/internal/operators/race.ts