I have this example:

type Getter = (myRecord: Record<string, string>) => string;
type Order = { id: string; items: string };

const getItemsFromOrder = (order: Order) => order.items;
const someHook = (getValue: Getter) => {
  // Contents don't matter
};

someHook(getItemsFromOrder);

My thinking is that this should work, since getItemsFromOrder is a function that takes param that is Order, which is a more specific case of Getter. However I get the error

Argument of type '(order: Order) => string' is not assignable to parameter of type 'Getter'.
  Types of parameters 'order' and 'myRecord' are incompatible.
    Type 'Record<string, string>' is missing the following properties from type 'Order': id, items

Why does someHook care that Getter is not assignable to Order? That’s not what I’m trying to do – I’m trying to assign Order to Getter, which should work, shouldn’t it?

How can I resolve this?