Utility Types

ELI5 — The Vibe Check

Utility types are TypeScript's built-in type transformers — like Instagram filters but for your interfaces. Partial makes everything optional, Pick grabs specific fields, Omit removes them. They transform types without rewriting them.

Real Talk

Built-in TypeScript generic types that facilitate common type transformations. Key utility types include Partial (all optional), Required (all required), Pick<T, K> (select properties), Omit<T, K> (exclude properties), Record<K, V> (key-value map), Readonly, and ReturnType.

Show Me The Code

interface User {
  id: number;
  name: string;
  email: string;
  role: 'admin' | 'user';
}

type CreateUser = Omit<User, 'id'>;
type UpdateUser = Partial<Pick<User, 'name' | 'email'>>;
type UserRecord = Record<string, User>;

When You'll Hear This

"Use Omit<User, 'id'> for your create endpoint instead of defining a whole new type." / "Partial is perfect for PATCH endpoints where any field might be updated."