export function unit(
  n: number, 
  singular: string, 
  plural: string, 
  f: (n: number, unit: string) => string = format
): string {
  return n > 1
    ? f(n, plural)
    : f(n, singular)
}

function format(n: number, unit: string): string {
  return `${n} ${unit}`
}