Sometimes, we want to extend types in TypeScript.

In this article, we’ll look at how to extend types in TypeScript.

How to extend types in TypeScript?

To extend types in TypeScript, we can use the extends keyword.

For instance, we write

type Event = {
  name: string;
  dateCreated: string;
  type: string;
};

interface UserEvent extends Event {
  UserId: string;
}

to create the UserEvent interface that extends the Event type.

We extend it by adding the string UserId field in UserEvent and inheriting the rest from Event.

Conclusion

To extend types in TypeScript, we can use the extends keyword.