Converting A Date From Dd-mm-yyyy To Dd/mm/yyyy In Javascript And Finding The Difference

I am trying to convert a date (obtained from a datepicker field) in DD-MM-YYYY to DD/MM/YYYY and get the difference (in years) between the two.. I have tried this so far: function

Solution 1:

I am trying to convert a date (obtained from a datepicker field) in DD-MM-YYYY to DD/MM/YYYY

That can be done using a simple replace:

'21-04-2014'.replace(/-/g,'/'); // 21/04/2014

and get the difference (in years) between the two

How do you want to do that? Years can have 365 or 366 days, which should be used? Do you want the answer in decimal years, or years and days, or years, months and days?

The following function will calculate the difference between two dates in whole days. If you use the precise parameter, it will not round the days and will give the difference down to the millisecond. Note that it expects to be given Date objects, not strings.

See snippet below.

To convert a string in the format dd-mm-yyyy or dd/mm/yyyy you can use:

functionparseDMY(s) {
  var b = s.split(/\D+/);
  returnnewDate(b[2], --b[1], b[0]);
}

To get the difference between say 1 January, 2012 and 22 July, 2014:

console.log(dateDifference(parseDMY('1-1-2012'), parseDMY('22-7-2014')));
// [2, 6, 21, 0, 0, "0.000"] or 2 years, 6 months, 21 days

And between 29 February, 2012 and 1 March, 2014 (leap years can be tricky):

console.log(dateDifference(parseDMY('29-2-2012'), parseDMY('1-3-2014')));
// [2, 0, 1, 0, 0, "0.000"] or2 years, 0 months, 1day

And between 31 January and 1 March 2014 (31 to 30 day months can be tricky too, simply adding one month to 31 Jan 2014 gives 3 March 2014):

console.log(dateDifference(parseDMY('31-1-2014'), parseDMY('1-3-2014')));
// [0, 1, 1, 0, 0, "0.000"] or0 years, 1month, 1day

// Given two date object, return the difference in years, months and days// Expects start date to be before end date// Default is to deal in whole days. For precise differences // (hours, minutes and seconds), set precise to truefunctiondateDifference(start, end, precise) {
      var timeDiff, years, months, days, hours, minutes, seconds;
    
      // Copy date objects so don't modify originalsvar s = newDate(+start);
      var e = newDate(+end);

      // If not precise, set h,m,s to zeroif (!precise) {
        s.setHours(0,0,0,0);
        e.setHours(0,0,0,0);
      }
    
      // Get estimate of year difference
      years = e.getFullYear() - s.getFullYear();
    
      // Add difference to start, if greater than end, remove one year// Note start from restored start date as adding and subtracting years// may not be symetric
      s.setFullYear(s.getFullYear() + years);
      if (s > e) {
        --years;
        s = newDate(+start);
        s.setFullYear(s.getFullYear() + years);
      }

      // Allow for leap year: 29-Feb + 1 year -> 1-Marif (start.getDate() != s.getDate()) {
        s.setDate(0);
      }
 
      // Get estimate of months
      months = e.getMonth() - s.getMonth();
      months += months < 0? 12 : 0;
    
      // Add difference to start, adjust if greater
      s.setMonth(s.getMonth() + months);

      if (s > e) {
        --months;
        s = newDate(+start);
        s.setFullYear(s.getFullYear() + years);
        s.setMonth(s.getMonth() + months);
      }

      // Allow for 31 day month rolling over to 1stif (start.getDate() != s.getDate()) {
        s.setDate(0);
      }

      // Get remaining time difference
      timeDiff = e - s;
      days     =  timeDiff / 8.64e7 | 0;
      hours    = (timeDiff % 8.64e7) / 3.6e6 | 0;
      minutes  = (timeDiff % 3.6e6) / 6e4 | 0;
      seconds  = ((timeDiff % 6e4) / 1e3).toFixed(3);
      return [years, months, days, hours, minutes, seconds];
    }

// Simple date string parser, doesn't validate valuesfunctionparseDMY(s) {
  var b = s.split(/\D/)
  returnnewDate(b[2], b[1]-1, b[0]);
}

functioncalcDiff(el) {
  var form = el.form;
  var start = parseDMY(form.startDate.value);
  var end   = parseDMY(form.endDate.value);
  if (isNaN(start) || isNaN(end)) return;
  var diff = dateDifference(start, end);
  document.getElementById('output').innerHTML = diff[0] + ' year'  + (diff[0] == 1? ' ' : 's ') +
                                                diff[1] + ' month' + (diff[1] == 1? ' ' : 's ') +
                                                diff[2] + ' day'   + (diff[2] == 1? '' : 's');
}

<formid="f"><table><tr><td>Start date (d/m/y)<td><inputname="startDate"value="20/03/2016"><tr><td>End date (d/m/y)<td><inputname="endDate"value="20/04/2017"><tr><td><inputtype="reset"><td><inputtype="button"onclick="calcDiff(this)"value="Get difference"></table></form><divid="output"></div>

This still has a few issues for leap years, update on the way…

Solution 2:

Try to make two Date- Objects like this

var date1 = newDate(2010, 6, 17);
var date2 = newDate(2013, 12, 18);
var diff = newDate(date2.getTime() - date1.getTime());

console.log(diff.getUTCFullYear() - 1970); // Gives difference as year// 3console.log(diff.getUTCMonth()); // Gives month count of difference// 6console.log(diff.getUTCDate() - 1); // Gives day count of difference// 4