06-May-2025

TypeScript provides several utility types to help developers work with types more effectively. These utility types can manipulate existing types, extract parts of types, or create new types based on existing ones. They enhance code readability, maintainability, and type safety.

Let’s explore a few commonly used utility types:

• Partial<Type>: Makes all properties in Type optional. Useful when dealing with forms or partial updates.

interface User {
  name: string;
  age: number;
  email?: string;
}

const partialUser: Partial<User> = { name: 'John' }; // No error, age and email are optional

• Required<Type>: Makes all properties in Type required. Helpful when you need to ensure all fields are present.

interface User {
  name: string;
  age: number;
  email?: string;
}

const requiredUser: Required<User> = { name: 'John', age: 30, email: 'john@example.com' }; // email is now required

• Readonly<Type>: Makes all properties in Type read-only. Prevents accidental modifications after object creation.

interface User {
  name: string;
  age: number;
}

const readonlyUser: Readonly<User> = { name: 'John', age: 30 };
readonlyUser.age = 31; // Error: Cannot assign to 'age' because it is a read-only property.

• Record<Keys, Type>: Creates a new type with keys specified by Keys and values of Type. Useful for creating mappings or dictionaries.

type Weekdays = 'Monday' | 'Tuesday' | 'Wednesday' | 'Thursday' | 'Friday';
const workSchedule: Record<Weekdays, number> = {
  Monday: 8,
  Tuesday: 9,
  Wednesday: 8,
  Thursday: 7,
  Friday: 6,
};

• Pick<Type, Keys>: Creates a new type by picking specific properties from Type specified by Keys.

interface User {
  name: string;
  age: number;
  email: string;
}

const userNameAndEmail: Pick<User, 'name' | 'email'> = { name: 'John', email: 'john@example.com' };

• Omit<Type, Keys>: Creates a new type by omitting specific properties from Type specified by Keys.

interface User {
  name: string;
  age: number;
  email: string;
}

const userWithoutEmail: Omit<User, 'email'> = { name: 'John', age: 30 };

These are just a few examples of the many utility types available in TypeScript. Leveraging these built-in utilities can significantly improve your type management and overall code quality. Refer to the official TypeScript documentation for a comprehensive list and more detailed explanations.