Fetch in parallel in JavaScript
JavaScript interview exercise on Async, 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 async fetchAll(ids, fetcher) where fetcher(id) returns a promise. Fetch all ids in parallel and resolve to the results in the same order as ids.
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.