Differences between type and interface in TypeScript

In TypeScript there are two ways to describe types: type and interface.

Interface

interface is used to describe the structure of objects and classes, as well as to extend other interfaces.

interface usage example:

typescript

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

interface Employee extends Person {
  position: string;
}

const employee: Employee = {
  name: "John",
  age: 30,
  position: "Developer"
};

interface allows using the extends keyword to extend other interfaces. This makes it convenient for working with object-oriented approach.

Type

type is more universal and can be used not only for objects, but also for other data types such as primitives, unions, intersections and others.

type usage example:

typescript

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

type Employee = Person & {
  position: string;
};

const employee: Employee = {
  name: "John",
  age: 30,
  position: "Developer"
};

When to use interface or type?

interface should be used when working with objects, especially if you need to extend or modify them using extends or implement in classes using implements.
type should be used when you need to work with universal types such as unions, intersections, tuples and primitives.

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Differences between type and interface in TypeScript

#Interface

#Type

#When to use interface or type?

Short Answer

Interface

Type

When to use interface or type?