Add a timeout to a promise in JavaScript
JavaScript interview exercise on Async, difficulty 3 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 withTimeout(promise, ms) that resolves with the promise's value if it settles within ms, otherwise rejects with an Error whose message is "timeout".
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.