Merge with defaults in TypeScript
TypeScript interview exercise on Objects, difficulty 2 of 3. Solve it in the editor beside a worked example; the tests run the moment you do.
Write withDefaults(defaults, options) that returns a new object where every key from defaults is present, overridden by options only when the option is not undefined. Neither input may be mutated.
Each exercise pairs a worked example with a twin problem to solve in a real editor; the tests run the moment you do. Progress is saved in your browser, and in your account if you sign in.