RxJS task: determine the output when using combineLatest with two streams with different delays. What will forkJoin output?

forkJoin in RxJS waits for all the provided Observables to complete and then emits an array of their last values. If one of the streams does not complete, forkJoin will not emit.

For example, if there are two streams with different delays, forkJoin will only emit after both streams have completed, providing an array of their last emitted values.

Example:

import { of, forkJoin, delay } from 'rxjs';

const stream1 = of('A').pipe(delay(1000));
const stream2 = of('B').pipe(delay(2000));

forkJoin([stream1, stream2]).subscribe(result => {
  console.log(result); // Will output ['A', 'B'] after about 2 seconds
});

Thus, forkJoin is useful when you need to wait for multiple asynchronous operations to complete and want to get their results at the same time.