date-fns/differenceInDays/index.js

"use strict";

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.default = differenceInDays;

var _index = _interopRequireDefault(require("../toDate/index.js"));

var _index2 = _interopRequireDefault(require("../differenceInCalendarDays/index.js"));

var _index3 = _interopRequireDefault(require("../compareAsc/index.js"));

var _index4 = _interopRequireDefault(require("../_lib/requiredArgs/index.js"));

function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }

/**
 * @name differenceInDays
 * @category Day Helpers
 * @summary Get the number of full days between the given dates.
 *
 * @description
 * Get the number of full day periods 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 full days
 * @throws {TypeError} 2 arguments required
 *
 * @example
 * // How many full days are between
 * // 2 July 2011 23:00:00 and 2 July 2012 00:00:00?
 * var result = differenceInDays(
 *   new Date(2012, 6, 2, 0, 0),
 *   new Date(2011, 6, 2, 23, 0)
 * )
 * //=> 365
 * // How many days are between
 * // 2 July 2011 23:59:00 and 3 July 2011 00:01:00?
 * var result = differenceInDays(
 *   new Date(2011, 6, 3, 0, 1),
 *   new Date(2011, 6, 2, 23, 59)
 * )
 * //=> 0
 */
function differenceInDays(dirtyDateLeft, dirtyDateRight) {
  (0, _index4.default)(2, arguments);
  var dateLeft = (0, _index.default)(dirtyDateLeft);
  var dateRight = (0, _index.default)(dirtyDateRight);
  var sign = (0, _index3.default)(dateLeft, dateRight);
  var difference = Math.abs((0, _index2.default)(dateLeft, dateRight));
  dateLeft.setDate(dateLeft.getDate() - sign * difference); // Math.abs(diff in full days - diff in calendar days) === 1 if last calendar day is not full
  // If so, result must be decreased by 1 in absolute value

  var isLastDayNotFull = (0, _index3.default)(dateLeft, dateRight) === -sign;
  var result = sign * (difference - isLastDayNotFull); // Prevent negative zero

  return result === 0 ? 0 : result;
}

module.exports = exports.default;