Calculate date difference in weeks (Javascript)

Question

I have two strings:

1387050870

and

2012-12-15

How can i calculate the difference between these two dates in weeks (52)?

I tried Math.round(1387050870-(Math.round(new Date('2012-12-15').getTime()/1000))/604800), but that doesn't seem to work.

I'll answer my question. I got NaN because '2012-15-12' is an "Invalid Date" — bjb568, Dec 14 '13 at 20:08
Changed my post. It returns everything, but not the expected result. — , Dec 14 '13 at 20:08
Tips: There is to need to used ` getTime` to convert it to millisecond. — Derek 朕會功夫, Dec 14 '13 at 20:08
Seems like your time string is not [rfc2822](http://tools.ietf.org/html/rfc2822#page-14) compliant — bjb568, Dec 14 '13 at 20:10
1) Gregorian calendars don't have a 15th month and typical `####-##-##` formats are parsed as `YYYY-MM-DD` when supported. 2) Order of operations divides before subtracting without grouping. — Jonathan Lonowski, Dec 14 '13 at 20:10
And also the date format Date accept is Date(year, month, day) — Derek 朕會功夫, Dec 14 '13 at 20:10
Okay, good to know. However, it returns a number, but i have no idea, what. — , Dec 14 '13 at 20:11
I've already fixed it. It was just a typo in the question. `new Date('2012-12-15')` returns a correct value. Time is not relevant. — , Dec 14 '13 at 20:14

Josiah Hester · Accepted Answer · 2013-12-14T20:19:38.323

7

The JavaScript Date object accepts milliseconds as its constructor, so convert first then try:

var a  = new Date(1387050870 * 1000);
var b = new Date("2012-12-15");
var weeks = Math.round((a-b)/ 604800000);

Which makes weeks 2239, which sounds close, since b is almost 43 years later * 52 weeks.

edited Dec 14 '13 at 20:19

answered Dec 14 '13 at 20:14

Josiah Hester

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Returns 2239 instead of 52 :) – Dec 14 '13 at 20:16
@user2368182 I got "Fri Jan 16 1970 17:17:30 GMT-0800 (PST)" from `new Date(1387050870);` – bjb568 Dec 14 '13 at 20:16
2

if first value is a unix timestamp need to multiply by 1000 first – charlietfl Dec 14 '13 at 20:17
1

Ah, you didnt specify the timestamp type, so I assumed milliseconds – Josiah Hester Dec 14 '13 at 20:17
@charlietfl Exactly. I think it should probably be `new Date(1387050870000);` which gives 2014 – bjb568 Dec 14 '13 at 20:18
`var a = new Date(1387050870000); var b = new Date("2012-12-15"); var weeks = Math.round((b-a)/ 604800000);` returns -52 – charlietfl Dec 14 '13 at 20:18
@charlietfl That's it :) Now, i get -52, which is correct. Ty. – Dec 14 '13 at 20:18
Just a little thing: The timestamp doesn't need to be a Date object. – Dec 14 '13 at 20:19
Use Math.floor instead of Math.round – olefrank Jan 11 '15 at 21:47
It depends on what do we means by different of weeks between two dates, do we mean the difference of week as a time interval difference or a calender interval as a difference, using the chosen solution for this questions, we get a 0 week difference for 4/01/2015 and 5/01/2015 but there is one week calender difference between the two – Noor Apr 23 '16 at 19:26

score 4 · Answer 2 · edited Dec 11 '15 at 19:27

4

Try this:

var date1 = new Date(1387050870 * 1000);
var date2 = new Date("2012-12-15");
var dif = Math.round(date1-date2);
alert(Math.round(dif/1000/60/60/24/7));

Here it is on jsfiddle!

edited Dec 11 '15 at 19:27

Peter Warrington

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answered Dec 14 '13 at 20:34

Nouphal.M

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Calculate date difference in weeks (Javascript)

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