Guided Notes
Utility Types
The built-in type helpers — Partial, Required, Readonly, Pick, Omit, Record, Exclude, Extract, NonNullable, ReturnType, Parameters and Awaited — with real use cases.
Transforming object types
Slide 1 / 4| Utility | Result | Typical use |
|---|---|---|
| Partial<T> | All properties optional | Update/patch payloads |
| Required<T> | All properties required | After defaults are applied |
| Readonly<T> | All properties readonly | Frozen config, state |
| Pick<T, K> | Only the listed keys | Public view of a model |
| Omit<T, K> | All except the listed keys | Create input without id/createdAt |
| Record<K, V> | Object with keys K, values V | Lookup tables |