How to combine multiple types into one interface?

Question

typescript

Good afternoon, maybe someone knows how I can create an interface of this kind:

interface StageState {
    [key: string]: Product[]; // *
    mode: string;
    categoryKey: string;
};

I have an object that stores the properties mode, categoryKey, and n a number of other properties with unknown names, it is only known that the remaining properties will always have the same type.

This example is incorrect and throws an error:

Answer 1

I can’t tell you how to do this using interface, I will be glad if someone tells you, but you can implement something like this using type:

type StageState = {
    mode: string; 
    categoryKey: string
} & Record<string, Product[]>