export type Point = { lat: number; lon: number };

type Integer<T extends number> = `${T}` extends `${string}.${string}` ? never
  : T;
export type Int = Integer<number>;
type Positive<T extends number> = `${T}` extends `-${string}` ? never
  : T;
type PositiveInteger<T extends number> = Positive<Integer<T>>;
export type Nat = PositiveInteger<number>;