Adding 1 day to a date variable

Question

In the spreadsheet I can have a date in one cell then in the next cell over I can type in =A1+1 and it adds 1 day to the date in cell A1. I would like to do the same thing in a script.

I can set a date variable to today's date using the following.

var dateTracking = "";
dateTracking = currentDate;

But if I try to add 1 to dateTracking then it changes the variable from date format to a string

dateTracking = dateTracking + 1;

I just want a quick easy solution to add 1 or more days to a date variable.

Perhaps this will help: https://stackoverflow.com/a/59555936/7215091 — Cooper, Jan 03 '20 at 04:41

score 2 · Answer 1 · answered Jan 05 '20 at 03:44

The previous answer worked for adding days but as I worked on my script I found myself needing to add months too. I could just add dayInMS*30.4167 but that would get me some variance in the day. I wanted the get the same date each month.

Here is a solution that I had found and it will work for adding days, months, years.

  var currentDate = new Date();
  var monthTest = "";
  var monthTest2 = "";
  var monthTest3 = "";
  var year = "";
  var month = "";
  var day = "";

  //start at today
  dateTracking = currentDate;

  //testing month
  day = dateTracking.getDate();
  month = dateTracking.getMonth();
  year = dateTracking.getYear();
  monthTest = new Date(year, month, day+1);
  monthTest2 = new Date(year, month+1, day);
  monthTest3 = new Date(year+1, month, day);

This solution is just as valid, it is up to your preferences! — ziganotschka, Jan 06 '20 at 08:18

score 0 · Accepted Answer · answered Jan 03 '20 at 11:53

With a script it is not as straightforward as in a spreadsheet

There are several ways to realize your request, but the easiest would probably be:

Convert your date to ms with getTime()
Add the equivalent of one day in ms (24*60*60*1000)
Transform the ms back to a date with new Date()

Sample:

var dateTracking=new Date() // returns the date of today
var dateTrackingInMs=dateTracking.getTime();
var dayInMs=24*60*60*1000;
var newDateTracking=new Date(dateTrackingInMs+dayInMs);

Adding 1 day to a date variable

2 Answers2

With a script it is not as straightforward as in a spreadsheet