TypeScript Utility Types: Complete Guide to Partial, Pick, Omit, Record and More

TypeScript ships with powerful built-in utility types that transform existing types. Stop writing repetitive type definitions—use these instead. The Most Useful Utility Types Partial<T> — Make All Properties Optional interface User { id : number ; name : string ; email : string ; } // All fields optional — perfect for update operations function updateUser ( id : number , updates : Partial < User > ) { return { ... getUser ( id ), ... updates }; } updateUser ( 1 , { name : " Alice " }); // valid updateUser ( 1 , { email : " new@example.com " }); // valid Required<T> — Make All Properties Required interface Config { timeout ?: number ; retries ?: number ; baseUrl ?: string ; } // All fields now required type StrictConfig = Required < Config > ; // { timeout: number; retries: number; baseUrl: string } Readonly<T> — Immutable Object interface Point { x : number ; y : number ; } const origin : Readonly < Point > = { x : 0 , y : 0 }; // origin.x = 1; // Error: Cannot assign to 'x' because it