@intility/bifrost-react/dist/utils/getDuration.js

React library for Intility's design system, Bifrost.

/**
 * Construct a Duration object based on start and end dates. Used internally by
 * `<FormatDuration>` and `<FormatRelativeTime>`.
 * @param start Start date
 * @param end End date
 * @returns A tuple containing the largest appropriate
 * Intl.RelativeTimeFormatUnit and the duration in that unit
 *
 * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Intl/DurationFormat/format
 */
export default function getDuration(start, end) {
  const durationInMs = end.getTime() - start.getTime();
  const seconds = Math.round(durationInMs / 1000);
  const minutes = seconds / 60;
  const hours = minutes / 60;
  const days = hours / 24;
  const months = days / 30.44; // Average days per month (365.25 / 12)
  const years = days / 365.25; // Account for leap years

  if (Math.abs(years) >= 1) return ["years", Math.round(years)];
  if (Math.abs(months) >= 1) return ["months", Math.round(months)];
  if (Math.abs(days) >= 1) return ["days", Math.round(days)];
  if (Math.abs(hours) >= 1) return ["hours", Math.round(hours)];
  if (Math.abs(minutes) >= 1) return ["minutes", Math.round(minutes)];
  return ["seconds", seconds];
}