RxJS switchmap example

 RxJS switchmap example, easy to understand

https://stackblitz.com/edit/rxjs-switchmap-example-1-vslesu?file=index.ts

import { interval } from 'rxjs';

import { take, switchMap, map, flatmap } from 'rxjs/operators';

let outer$ = interval(5000).pipe(take(2));

let combined$ = outer$.pipe(

switchMap((x) => {

return interval(2000).pipe(

take(3),

map((y) => `outer ${x}: inner ${y}`)

);

})

);

/*

5 seconds: the inner observable is started

7 seconds: 0 0

9 seconds: 0 1

10 seconds (now the second outer$ comes, the inner observable is unsubscribed)

12 seconds: 1 0

14 seconds: 1 1

16 seconds: 1 2

*/

console.log(new Date().toISOString());

combined$.subscribe((result) =>

console.log(new Date().toISOString() + ' ' + `${result}`)

);