Nested subscribe to inner Observables

http-map-subscribe.ts

import { map } from 'rxjs/operators';
import { ajax } from 'rxjs/ajax';
import { of } from 'rxjs';

const pokemonId$ = of(1, 5, 6);

function getPokemonName(id: number) {
  return ajax.getJSON(`https://pokeapi.co/api/v2/pokemon/${id}`).pipe(
    map(({ name }) => name));
}

pokemonId$
  .pipe(
    map(id => getPokemonName(id)),
  )
  .subscribe(innerObservable$ => innerObservable$.subscribe(console.log));
// Output: bulbasaur, charizard, charmeleon