Is it possible to require only some specified key

问题:

There is a type from a 3rd party:

interface UpdateRequest {
  data?: ValueRange[];
  options?: Options
}

I want to create a method with this signature:

update(params: RequiredOnly<UpdateRequest, 'data'>) {
  //...
}

The RequiredOnly type utility will make only the key 'data' is required, not both 'data' and 'options' like what Required does.

Is it possible to create that RequiredOnly type utility?

I'm stucking here:

type RequiredOnly<T, a extends keyof T> = { 
  [K in keyof T extends a ? a : never ]-?: T[K] 
} 

回答1:

You can use Pick and Required and intersect back with the original type to get back the other optional properties

type RequireSome<T, K extends keyof T> = Required< Pick<T, K>> & T;