Starting the week on Monday with isoWeekday

Question

I m creating a calendar where I print out weeks in a tabular format  One requirement is that I be able to start the weeks either on Monday or Sunday  as per some user option  I m having a hard time using moment s isoWeekday method      Start of some date range  Can be any day of the week  var startOfPeriod   moment  2013-06-23T00 00 00            We begin on the start of the first week         Mon Tues Wed Thur Fri Sat Sun        20  21   22  23   24  25  26     begin   moment startOfPeriod  isoWeekday 1      will pull from user setting  console log begin isoWeekday        1 - all good     Let s get the beginning of this first week  respecting the isoWeekday begin startOf  week     console log begin isoWeekday        7 - what happened         Get column headers for  var i 0  i lt 7  i          console log begin format  ddd        I want Monday first      begin add  d   1       jsFiddle  EDIT I misunderstood what isoWeekday was actually doing  I thought it set the  which day of the week is the first day of the week  variable  that doesn t exist   What it actually does is simply changes the day of the week  just like moment weekday    but uses a 1-7 range instead of the 0-6

User · Answer

Here is a more generic solution for any given weekday  Working demo on jsfiddle  var myIsoWeekDay   2     say our weeks start on tuesday  for monday you would type 1  etc   var startOfPeriod   moment  2013-06-23T00 00 00        how many days do we have to substract  var daysToSubtract   moment startOfPeriod  isoWeekday    gt   myIsoWeekDay       moment startOfPeriod  isoWeekday   - myIsoWeekDay       7   moment startOfPeriod  isoWeekday   - myIsoWeekDay      subtract days from start of period var begin   moment startOfPeriod  subtract  d   daysToSubtract

User · Answer

This way you can set the initial day of the week    moment locale  en         week            dow  6           moment locale  en      Make sure to use it with moment   weekday 1   instead of moment isoWeekday 1

User · Answer

For those who want isoWeek to be the default you can modify moment s behaviour as such   const moment   require  moment    const proto   Object getPrototypeOf moment      const  startOf  endOf    proto  proto startOf   function period      if  period      week         period    isoWeek         return startOf call this  period      proto endOf   function period      if  period      week         period    isoWeek         return endOf call this  period        Now you can simply use someDate startOf  week   without worrying you ll get sunday or having to think about whether to use isoweek or isoWeek etc   Plus you can store this in a variable like const period    week  and use it safely in subtract   or add   operations  e g  moment   subtract 1  period  startOf period    This won t work with period being isoWeek

User · Answer

thought I would add this for any future peeps    It will always make sure that its monday if needed  can also be used to always ensure sunday   For me I always need monday  but local is dependant on the machine being used  and this is an easy fix   var begin   moment   isoWeekday 1  startOf  week    var begin2   moment   startOf  week       could check to see if day 1   Sunday  then add 1 day    my mac on bst still treats day 1 as sunday      var firstDay   moment   startOf  week   format  dddd        Sunday         moment   startOf  week   add  d  1  format  dddd DD-MM-YYYY      moment   startOf  week   format  dddd DD-MM-YYYY     document body innerHTML     lt b gt could be monday or sunday depending on client   lt  b gt  lt br   gt      begin format  dddd DD-MM-YYYY        lt br   gt  lt br   gt   lt b gt should be monday  lt  b gt   lt br gt     firstDay      lt br gt  lt br gt   lt b gt could also be sunday or monday  lt  b gt  lt br gt       begin2 format  dddd DD-MM-YYYY

User · Answer

Call startOf before isoWeekday   var begin   moment date  startOf  week   isoWeekday 1     Working demo

User · Answer

try using begin startOf  isoWeek    instead of begin startOf  week

[javascript] Starting the week on Monday with isoWeekday()

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