What is the difference between type and interface?

Understanding when to use type vs interface.

What You'll Learn

Differences between type and interface
When to use each
Best practices

Comparison

Feature	Type	Interface
Extend	& (intersection)	extends
Declaration merging	No	Yes
Primitives/Unions	Yes	No
Computed properties	Yes	No

Interface

code.tsTypeScript

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

// Extending
interface Admin extends User {
  role: string;
}

// Declaration merging
interface User {
  email: string; // Merges with above
}

Type

code.tsTypeScript

type User = {
  name: string;
  age: number;
};

// Extending with intersection
type Admin = User & {
  role: string;
};

// Union types (interface can't do this)
type Status = "pending" | "approved" | "rejected";

// Primitive types
type ID = string | number;

Best Practice

Use interface for object shapes that might be extended
Use type for unions, primitives, and complex types
Be consistent within your codebase

What are the basic types in TypeScript?

What are Union Types in TypeScript?