I have an interface like that:
interface Car {
model: string;
owners: string[];
}
And I want to get only array properties:
type NewCar = OnlyArrays<Car>
And this will be equal to:
type NewCar = {
owners: string[];
}
Type it's not important, array just for example.
I've tried this code but it doesn't work:
function getCar<T = Car>(id: string): { [P in keyof T]: T[P] extends array ? string[] : string; };
CodePudding user response:
You can declare a mapped type and remap the keys (docs) to include only those keys for which the value extends an array:
type OnlyArrays<T> = {
[K in keyof T as T[K] extends Array<infer _> ? K : never]: T[K]
}
type NewCar = OnlyArrays<Car>
// type NewCar = { owners: string[] }