First Day of Week and First Week of Year1.0.0+

  1. // From 2.12.0 onward
  2. moment.updateLocale('en', {
  3.     week : {
  4.         dow : Int,
  5.         doy : Int
  6.      }
  7. });
  8. // From 2.8.1 to 2.11.2
  9. moment.locale('en', {
  10.     week : {
  11.         dow : Int,
  12.         doy : Int
  13.     }
  14. });
  16. // Deprecated in 2.8.1
  17. moment.lang('en', {
  18.     week : {
  19.         dow : Int,
  20.         doy : Int
  21.     }
  22. });

Locale#week.dow should be an integer representing the first day of the week, 0 is Sunday, 1 is Monday, …, 6 is Saturday.

Locale#week.doy should be an integer. doy is used together with dow to determine the first week of the year. doy is calculated as 7 + dow - janX, where janX is the first day of January that must belong to the first week of the year.

  1. // ISO-8601, Europe
  2. moment.updateLocale("en", { week: {
  3.   dow: 1, // First day of week is Monday
  4.   doy: 4  // First week of year must contain 4 January (7 + 1 - 4)
  5. }});
  7. // US, Canada
  8. moment.updateLocale("en", { week: {
  9.   dow: 0, // First day of week is Sunday
  10.   doy: 6  // First week of year must contain 1 January (7 + 0 - 1)
  11. }});
  13. // Many Arab countries
  14. moment.updateLocale("en", { week: {
  15.   dow: 6, // First day of week is Saturday
  16.   doy: 12 // First week of year must contain 1 January (7 + 6 - 1)
  17. }});
  19. // Also common
  20. moment.updateLocale("en", { week: {
  21.   dow: 1, // First day of week is Monday
  22.   doy: 7  // First week of year must contain 1 January (7 + 1 - 1)
  23. }});