Difference between two dates 6 months should not be more than 6 months

Question

I need to find the difference between two dates. If the difference is greater than 6 then display a message in Java Script.

I tried below logic but somehow it is not working.

var sFromDate = new Date(Mon Jun 01 2020 00:00:00 GMT-0400);
var sToDate = new Date(Mon Nov 30 2020 23:59:59 GMT-0500);
var diff = sToDate.getTime() - sFromDate.getTime();
diff = diff / (1000 * 60 * 60 * 24 * 30);
if (diff > 6) {
    alert('Not more than 6 months')
}

In the above example. I am still getting the alert even the range is within 6 months.

Can someone help me in finding the logic the difference between 2 dates should not be more than 6 months.

Check the [syntax for `new Date()`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Date/Date). Use commas or strings. — Rojo, Dec 15 '20 at 16:54

score 0 · Answer 1 · answered Dec 15 '20 at 16:58

You can check this answer. In your case the code would be-

function monthDiff(dateFrom, dateTo) {
 return dateTo.getMonth() - dateFrom.getMonth() + 
   (12 * (dateTo.getFullYear() - dateFrom.getFullYear()))
}

const sFromDate = new Date("Mon Jan 01 2020 00:00:00 GMT-0400");
const sToDate = new Date("Mon Nov 30 2020 23:59:59 GMT-0500");

const diff = monthDiff(sFromDate, sToDate);

if (diff > 6) alert('Not more than 6 months');

console.log('Diff in months: ', diff);

score 0 · Answer 2 · answered Dec 15 '20 at 17:05

Take the first date and add 6 months, then check that against the second date:

const date1 = new Date('Mon Jun 01 2020 00:00:00 GMT-0400');
const date2 = new Date('Mon Nov 30 2020 23:59:59 GMT-0500');
const plus6Months = new Date(date1.getYear(), date1.getMonth()+6, date1.getDay());

if (date2.getTime() > plus6Months.getTime())
  console.log('dates are more than 6 months apart');
else if (date2.getTime() < plus6Months.getTime())
  console.log('dates are less than 6 months apart');
else 
  console.log('dates are exactly 6 months apart');

Luca Ognissante · Answer 3 · 2020-12-16T07:51:46.560

-1

var sFromDate = new Date(Mon Jun 01 2020 00:00:00 GMT-0400);
var sToDate = new Date(Mon Nov 30 2020 23:59:59 GMT-0500);
var months = (sToDate.getFullYear() - sFromDate.getFullYear()) * 12;
months -= sFromDate.getMonth();
months += sToDate.getMonth();
if (months > 6) {
    alert('Not more than 6 months')
}

edited Dec 16 '20 at 07:51

answered Dec 15 '20 at 16:53

Luca Ognissante

27
4

2

This could benefit from an explanation – Rojo Dec 15 '20 at 16:54
2

... especially as it isn't valid JS. Did you mean to pass strings to the Date constructor instead? Did you mean to *call* `getFullYear`? – Scott Sauyet Dec 15 '20 at 16:56

Difference between two dates 6 months should not be more than 6 months

3 Answers3