Wait for all: forkJoin in RxJS
RxJS interview exercise on Combining, difficulty 2 of 3. Solve it in the editor beside a worked example, or cold in Interview mode with the example hidden; the tests run the moment you do.
Write loadAll(requests): given an array of observables, emit one array with each one's last value once they have all completed, then complete. An empty array completes without emitting. If any request errors, error.
Each exercise pairs a worked example with a twin problem to solve in a real editor; the tests run the moment you do. Interview mode hides the example: solve it from memory, without the hint or the solution, and it counts as solved cold. Progress is saved in your browser, and in your account if you sign in.