forkJoin vs. race with timer

example.ts

import { timer, race, forkJoin, of, throwError } from 'rxjs';
import { concatMap, map, catchError } from 'rxjs/operators';

let resolvePromise;
let rejectPromise;

const prom = new Promise((resolve, reject) => {
  resolvePromise = resolve;
  rejectPromise = reject;
});

function doForkJoin() {
  console.time('forkJoin');
  forkJoin([prom, timer(100)])
    .pipe(
      map((val) => `"${val}"`),
      catchError(() => of('resurrection'))
    )
    .subscribe(
      (val) => console.log('Subscribed val:', val),
      (err) => {
        console.log('Error happened:', err);
        console.error('hmm');
        console.timeEnd('forkJoin');
      },
      () => {
        console.log('complete');
        console.timeEnd('forkJoin');
      }
    );

  setTimeout(() => {
    rejectPromise('rejected promise');
    resolvePromise('resolved promise');
  }, 500);
}

/* 
timer(1000).pipe(take(6)).subscribe(
  (val) => console.log('timer val', val),
  err => console.error(err),
  () => console.log('timer complete')
);
 */

function doRace() {
  console.time('race');
  race([prom, timer(100).pipe(concatMap(() => throwError('💥')))])
    .pipe(
      map((val) => `"${val}"`),
      catchError(() => of('resurrection'))
    )
    .subscribe(
      (val) => console.log('Subscribed val:', val),
      (err) => {
        console.log('Error happened:', err);
        console.error('hmm');
        console.timeEnd('race');
      },
      () => {
        console.timeEnd('race');
        console.log('complete');
      }
    );

  setTimeout(() => {
    resolvePromise('resolved promise');
    rejectPromise('rejected promise');
  }, 500);
}

function doForkJoinWithoutPromise() {
  console.time('doForkJoinWithoutPromise');
  race([timer(500), timer(100)])
    .pipe(
      map((val) => `"${val}"`),
      catchError(() => of('resurrection'))
    )
    .subscribe(
      (val) => console.log('doForkJoinWithoutPromise val:', val),
      (err) => {
        console.log('Error happened:', err);
        console.error('hmm');
        console.timeEnd('doForkJoinWithoutPromise');
      },
      () => {
        console.timeEnd('doForkJoinWithoutPromise');
        console.log('doForkJoinWithoutPromise complete');
      }
    );
}

// doForkJoin();
// doForkJoinWithoutPromise();
doRace();