useDebounced in Vue
Vue interview exercise on Composables, 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 useDebounced<T>(source: Ref<T>, ms: number) returning a ref that starts equal to the source and takes a new value only once the source has been unchanged for ms milliseconds (a watcher with a timer that each change restarts). The timer must be cleared when the component unmounts.
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.