Generic typing a hash-map with dynamic key and T array

I have a JSON like this. I need an add a type of this JSON. As you can see this is a hash-map structure let's see how we declare the hash-map interface in typescript.

I declared this hash-map in my useState like that.

  const [faqCategories, setFaqCategories] = useState<FAQ[]>([]);

We are declaring hash-map like that in typescript.

export interface FAQ {
  [key: string]: Category[];
} 

The whole type system like this for this JSON.

export interface Question {
  question: string;
  answer: string;
}
export interface Category {
  categoryName: string;
  iconName: string;
  questions: Question[];
}

export interface FAQ {
  [key: string]: Category[];
}

Source: https://stackoverflow.com/a/52913569/10694425