What are the differences between mapped types and utility types in TypeScript?

What are the differences between mapped types and utility types in TypeScript?

Mapped types allow you to create new types by transforming properties of existing types, while utility types are predefined types that provide common type transformations.

Can you give me an example of a mapped type?

Sure! A mapped type can be created like this: type Readonly<T> = { readonly [K in keyof T]: T[K] }; This makes all properties of T readonly.

And what about utility types? Can you list some?

Common utility types include Partial, Required, Readonly, and Record. Each serves a specific purpose in type manipulation.

How do I decide when to use a mapped type versus a utility type?

Use mapped types when you need to create a new type based on existing properties, and utility types for common transformations that are already defined.