RxJS switchMap sample

switchMap-sample.ts

import { of, interval, never } from "rxjs";
import { map, switchMap } from "rxjs/operators";

const a = of(1, 2, 3, 4);
const b = of(1, 2, 3, 4).pipe(map(e => e * 10));
const c = of(1, 2, 3, 4).pipe(map(e => e * 100));

const main = interval(1000).pipe(
  switchMap(i => {
    switch (i % 3) {
      case 0:
        return a;
      case 1:
        return b;
      case 2:
        return c;
    }
    return never();
  })
);

main.subscribe(console.log);