TypeScript Utility Types You Actually Use

TypeScript's built-in utility types eliminate entire categories of boilerplate. Here are the ones that show up in nearly every codebase I touch.

Partial — optional form state

Partial<T> makes every key in T optional. Perfect for update payloads where you only send changed fields, or for controlled form state where the user hasn't filled everything yet.

type ProjectUpdate = Partial<Project>;
// { slug?: string; title?: string; ... }

Pick and Omit — slicing your types

Instead of duplicating type definitions, Pick and Omit derive them from a source of truth. A card component that only needs slug, title, and excerpt shouldn't accept the whole entity.

type PostCard = Pick<BlogPost, 'slug' | 'title' | 'excerpt'>;
type PublicProject = Omit<Project, 'internalNotes'>;

Record — typed dictionaries

Record<K, V> is the right tool whenever you have a fixed set of keys mapping to a value type. Category colour maps, feature flag objects, route config tables — all become self-documenting.

const CATEGORY_COLORS: Record<Category, string> = {
  Frontend: 'text-accent-success',
  Backend:  'text-accent-primary',
  Fullstack: 'text-accent-secondary',
};

ReturnType and Awaited

When a function's return type is complex and you don't control its definition, ReturnType extracts it. Wrap it in Awaited to unwrap promises — essential for inferring types from server actions and async data-fetching functions without importing intermediate types.

type Projects = Awaited<ReturnType<typeof getProjects>>;
// Project[]