I have this type:

type DropdownProps<T> = {
  data: T[],
  id: keyof T,
};

The problem is that if I now try to use id it will have the any. I need to make sure that id is either type number or string.

Basically, I want to pass an array of objects and one of the object's keys. That key should return a value of the type string or number.

I don't want to require the key to be called id, but if that's necessary to make it work it would be fine.

CodePudding user response：

Intersect it with the types you want:

type DropdownProps<T> = {
  data: T[],
  id: keyof T & (string | number),
};

Playground

CodePudding user response：

// to limit T type keys:
type DropdownProps<
  T extends Record<string | number, any>,
  K extends keyof T
> = {
  data: T[],
  myId: K,
};

// to limit picked keys
type DropdownProps<
  T extends Record<any, any>,
  K extends (keyof T) & (string | number)
> = {
  data: T[],
  myId: K,
};