How do I type an object with known and unknown keys in TypeScript

Question

I am looking for a way to create TypeScript types for the following object that has two known keys and one unknown key that has a known type:

interface Combo         


        

Answer 1

Nice one @jcalz

It gave me some good insight to get where I wanted. I have like a BaseObject with some known properties and the BaseObject can have as many BaseObjects as it wants.

type BaseObject = { known: boolean, field: number };
type CoolType> = BaseObject & Record;
const asComboObject = (x: C & CoolType): C => x;

const tooManyExtraKeys = asComboObject({
     known: true,
     field: 123,
     unknownName: {
         known: false,
         field: 333
     },
     anAdditionalName: {
         known: true,
         field: 444
     },
});

and this way I can get type checks for the structure that I already had without changing too much.

ty