combineLatest

combineLatest operator combines multiple observables with last value emitted by each one.

Example: combineLatest operator

import { combineLatest, timer } from 'rxjs';
import { map, take } from 'rxjs/operators';

const numberToAlphabet = (n) => String.fromCharCode(97+n);

const timer1$ = timer(0, 3000).pipe(take(5));
const timer2$ = timer(1500, 2000).pipe(map(numberToAlphabet), take(9));

const combined$ = combineLatest(timer1$, timer2$);

Example: combineLatest with multiple observables

import { combineLatest, timer } from 'rxjs';
import { map } from 'rxjs/operators';

const t1$ = timer(0, 4000);
const t2$ = timer(1000, 4000)
const t3$ = timer(2000, 4000)

const combined$ = combineLatest(t1$, t2$, t3$);

Official Doc: rxjs.combineLatest