index.js 1.9 KB

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  1. "use strict";
  2. var _interopRequireDefault = require("@babel/runtime/helpers/interopRequireDefault").default;
  3. Object.defineProperty(exports, "__esModule", {
  4. value: true
  5. });
  6. exports.default = differenceInCalendarISOWeeks;
  7. var _index = _interopRequireDefault(require("../_lib/getTimezoneOffsetInMilliseconds/index.js"));
  8. var _index2 = _interopRequireDefault(require("../startOfISOWeek/index.js"));
  9. var _index3 = _interopRequireDefault(require("../_lib/requiredArgs/index.js"));
  10. var MILLISECONDS_IN_WEEK = 604800000;
  11. /**
  12. * @name differenceInCalendarISOWeeks
  13. * @category ISO Week Helpers
  14. * @summary Get the number of calendar ISO weeks between the given dates.
  15. *
  16. * @description
  17. * Get the number of calendar ISO weeks between the given dates.
  18. *
  19. * ISO week-numbering year: http://en.wikipedia.org/wiki/ISO_week_date
  20. *
  21. * @param {Date|Number} dateLeft - the later date
  22. * @param {Date|Number} dateRight - the earlier date
  23. * @returns {Number} the number of calendar ISO weeks
  24. * @throws {TypeError} 2 arguments required
  25. *
  26. * @example
  27. * // How many calendar ISO weeks are between 6 July 2014 and 21 July 2014?
  28. * const result = differenceInCalendarISOWeeks(
  29. * new Date(2014, 6, 21),
  30. * new Date(2014, 6, 6)
  31. * )
  32. * //=> 3
  33. */
  34. function differenceInCalendarISOWeeks(dirtyDateLeft, dirtyDateRight) {
  35. (0, _index3.default)(2, arguments);
  36. var startOfISOWeekLeft = (0, _index2.default)(dirtyDateLeft);
  37. var startOfISOWeekRight = (0, _index2.default)(dirtyDateRight);
  38. var timestampLeft = startOfISOWeekLeft.getTime() - (0, _index.default)(startOfISOWeekLeft);
  39. var timestampRight = startOfISOWeekRight.getTime() - (0, _index.default)(startOfISOWeekRight);
  40. // Round the number of days to the nearest integer
  41. // because the number of milliseconds in a week is not constant
  42. // (e.g. it's different in the week of the daylight saving time clock shift)
  43. return Math.round((timestampLeft - timestampRight) / MILLISECONDS_IN_WEEK);
  44. }
  45. module.exports = exports.default;