Source: differenceInMilliseconds/index.js

import toDate from '../toDate/index'
import requiredArgs from '../_lib/requiredArgs/index'

/**
 * @name differenceInMilliseconds
 * @category Millisecond Helpers
 * @summary Get the number of milliseconds between the given dates.
 *
 * @description
 * Get the number of milliseconds between the given dates.
 *
 * ### v2.0.0 breaking changes:
 *
 * - [Changes that are common for the whole library](https://github.com/date-fns/date-fns/blob/master/docs/upgradeGuide.md#Common-Changes).
 *
 * @param {Date|Number} dateLeft - the later date
 * @param {Date|Number} dateRight - the earlier date
 * @returns {Number} the number of milliseconds
 * @throws {TypeError} 2 arguments required
 *
 * @example
 * // How many milliseconds are between
 * // 2 July 2014 12:30:20.600 and 2 July 2014 12:30:21.700?
 * var result = differenceInMilliseconds(
 *   new Date(2014, 6, 2, 12, 30, 21, 700),
 *   new Date(2014, 6, 2, 12, 30, 20, 600)
 * )
 * //=> 1100
 */
export default function differenceInMilliseconds(
  dirtyDateLeft,
  dirtyDateRight
) {
  requiredArgs(2, arguments)

  var dateLeft = toDate(dirtyDateLeft)
  var dateRight = toDate(dirtyDateRight)
  return dateLeft.getTime() - dateRight.getTime()
}