narrow.ts

type Narrow<T> =
    | (T extends Function ? T : never)
    | (T extends string | number | bigint | boolean ? T : never)
    | (T extends [] ? [] : never)
    | {
          [K in keyof T]: Narrow<T[K]>;
      };

function narrow<T extends object>(input: Narrow<T>){
    return input
}