Listening on window in Vue
Vue interview exercise on Lifecycle & refs, 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 KeyWatcher: it shows <p>Last key: <kbd>?</kbd></p> and listens to keydown on window (added on mount, removed on unmount). Each key updates the <kbd> and emits `key` with event.key; when the key is "Escape" it also emits `escape`. After unmounting, a keydown must do nothing.
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.