intervalToDuration

// Get the duration between January 15, 1929 and April 4, 1968.
intervalToDuration({
  start: new Date(1929, 0, 15, 12, 0, 0),
  end: new Date(1968, 3, 4, 19, 5, 0)
})
// => { years: 39, months: 2, days: 20, hours: 7, minutes: 5, seconds: 0 }