I use Pick, but how could I write a generic PickMulti which can pick multiple fields?
interface MyInterface {
a: number,
b: number,
c: number
}
// this works, but I would like a generic one in number of fields
type AB = Pick<Pick<MyInterface, 'a'>, 'b'>;
// Something like this:
type PickMulti = /* how to write this?*/;
type AB = PickMulti<MyInterface, ['a', 'b']>
Pick already works with multiple fields you just need to provide them as a union, not a tuple/array type:
interface MyInterface {
a: number,
b: number,
c: number
}
type AB = Pick<MyInterface, 'a' | 'b'>;
You may want to work with arrays as in your example:
type PickMulti = /* how to write this?*/;
type AB = PickMulti<MyInterface, ['a', 'b']>
So if you have array:
const fields = Object.keys(object).filter(...)
// or
const fields = ['a', 'b']
It may be solved like this:
const pickArray = [...fields] as const;
type pickUnion = typeof pickArray[number];
type PickAB = Pick<MyInterface, pickUnion & keyof MyInterface>;
You can try something like this
type PickMulti<T, K extends (keyof T)[]> = {
[Key in K[number]]: T[Key];
};
type AB = PickMulti<MyInterface, ['a', 'b']>
