useForm in React
React interview exercise on Custom hooks, 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 useForm(initial) returning { values, handleChange, reset, dirty }: handleChange takes a change event and updates the field named by e.target.name (checkboxes use e.target.checked), reset returns to the initial values, and dirty is true while any value differs from its initial one.
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.