What are some examples of mapped types in TypeScript?

Can you explain what mapped types are in TypeScript?

Mapped types in TypeScript allow you to create new types by transforming properties of existing types. They are useful for creating variations of types.

Can you give me some examples of mapped types?

Sure! For instance, you can use Record<K, T> to create a type with keys of type K and values of type T. Another example is using the keyof operator to create a type that has the same keys as another type but with different value types.

What about using mapped types with optional properties?

You can create a mapped type that makes all properties optional by using the ? modifier. For example, type Partial<T> = { [P in keyof T]?: T[P] } makes all properties of T optional.

Are there any limitations to using mapped types?

Yes, mapped types can only transform properties of existing types and cannot add new properties. Also, they cannot be used with union types directly.