javascript how to sort by date

Question

For sorting array by date is used following method:

function sortDate(sortValues)
{
  sortValues.sort(function (a,b)
  {
    a=new Date(a.date);
    b=new Date(b.date);
    if (a<b)
    {
      return -1;
    }
    if (a>b)
    {
      return 1;
    }
    return 0; 
  })
  return sortValues;
}

This method works oddly:

In first case method works correctly (returns array sorted by date), but on another jsp-page it doesn't work (returns the same array, which receives. Format of dates is identical). The most strange thing is during of usage outputs ("alert(a+" "+b);") values of vars "a", "b" are equal "Invalid Date". But this fact doesn't affect in first case.

Keep in mind that Java is not the same as JavaScript. JavaScript is commonly shortend to `js` to avoid confusion with `Java Server Pages` (`jsp`). — Halcyon, May 16 '14 at 13:12
Verify that `a.date` and `b.date` are valid date strings. JavaScript seems to thing they are not. — Halcyon, May 16 '14 at 13:13
definately, you are not able to send right `sortValues` to the jsp page. `invalid date` in the output seems to be saying that. — Ashish Negi, May 16 '14 at 13:24
You can find some useful answers to this topic here: **[Sort Javascript Object Array By Date](http://stackoverflow.com/a/26759127/2247494)** — jherax, Nov 05 '14 at 15:29

Grainier · Answer 1 · 2014-05-16T13:24:10.897

0

First make sure that a.date and b.date are valid date strings, which can create a Date object. Refer this to find out whether they are valid date strings : link

Then try this.

function sortDate(sortValues)
{
    sortValues.sort(function(a,b){
        var date_a=new Date(a.date).getTime();
        var date_b=new Date(b.date).getTime();
        return date_a > date_b;
    }
    return sortValues;
};

edited May 16 '14 at 13:24

answered May 16 '14 at 13:17

Grainier

1,595
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this method is not right. the OP method is right. returning -1, 1, 0 makes the sorting algorithm work right. also, your link does not say anything about valid date strings. can you explain it here ? – Ashish Negi May 16 '14 at 13:30
Thank you for help, but it seems to be it doesn't work – slider May 16 '14 at 13:30
Can you provide the array you want to sort? – Grainier May 16 '14 at 13:33

kennebec · Answer 2 · 2014-05-16T14:53:40.273

You can get timestamps from strings with Date.parse.

This filters out invalid date input by testing with isFinite before sorting:

function sortDates(arr){
    return arr.map(Date.parse).filter(isFinite).sort(function(a, b){
        return a-b
    });
}

//test:

var A1=

['9/8/2007, 4:51:00 PM', '11/8/2001, 1:43:00 PM', '5/6/2031, 9:12:00 AM', '10/27/2013, 2:12:00 AM', '10/18/2004, 1:06:00 PM', '8/20/2000, 4:18:00 AM', '8/17/2015, 5:55:00 PM', '10/30/2000, 3:44:00 PM', '12/8/2002, 1:45:00 PM', '1/21/2000, 11:11:00 AM', '6/10/2000, 3:52:00 PM', '12/17/2012, 12:29:00 AM', '1/11/2000, 12:54:00 PM', '1/27/2007, 11:14:00 PM', '4/30/2000, 8:07:00 PM', '7/26/2019, 10:15:00 PM', '2/10/2000, 8:25:00 AM', '1/26/2009, 12:13:00 PM', '4/29/2005, 10:38:00 PM', '1/24/2030, 3:51:00 AM', '1/31/2000, 1:43:00 PM', '10/8/2009, 1:33:00 AM', '8/4/2020, 11:31:00 AM', '4/27/2026, 10:10:00 PM', '2/13/2025, 6:05:00 PM', '7/29/2002, 3:04:00 PM', '7/18/2010, 3:17:00 AM', '2/5/2012, 7:09:00 PM', '5/20/2003, 5:44:00 PM', '9/15/2021, 1:32:00 AM', '4/21/2001, 11:14:00 AM', '11/7/2005, 9:18:00 AM', '7/16/2018, 9:21:00 AM', '10/13/2028, 7:29:00 AM', '7/6/2017, 1:39:00 PM', '7/26/2016, 6:19:00 AM', '5/18/2008, 12:45:00 PM', '3/21/2002, 7:05:00 AM', '3/22/2000, 3:51:00 PM', '9/6/2014, 1:34:00 AM', 'bob', '4/8/2004, 1:56:00 PM', '12/5/2023, 6:58:00 AM', '1/9/2001, 9:36:00 PM', '10/28/2003, 7:50:00 PM', '10/26/2022, 2:06:00 PM', '7/5/2027, 8:57:00 AM', '7/30/2001, 5:04:00 PM', '6/19/2006, 4:24:00 PM', '4/27/2011, 12:12:00 PM', '1/1/2000, 6:41:00 PM'];

var A2=sortDates(A1);

/* returned value: (Array)

946770060000, 947613240000, 948471060000, 949344180000, 950189100000, 953754660000, 957139620000, 960666720000, 966759480000, 972935040000, 979094160000, 987866040000, 996527040000, 1005244980000, 1016708700000, 1027969440000, 1039373100000, 1053467040000, 1067385000000, 1081446960000, 1098119160000, 1114828680000, 1131373080000, 1150748640000, 1169957640000, 1189284660000, 1211129100000, 1232989980000, 1254979980000, 1279437420000, 1303920720000, 1328486940000, 1355722140000, 1382854320000, 1409981640000, 1439848500000, 1469528340000, 1499362740000, 1531747260000, 1564193700000, 1596555060000, 1631683920000, 1666807560000, 1701777480000, 1739487900000, 1777342200000, 1814792220000, 1855049340000, 1895475060000, 1935839520000 */

You can then convert the timestamps back to dates or strings, if needed.

A2.map(function(itm){   
    return new Date(itm).toLocaleString();
}).join(', ');

/* returned value: (String)

1/1/2000, 6:41:00 PM, 1/11/2000, 12:54:00 PM, 1/21/2000, 11:11:00 AM, 1/31/2000, 1:43:00 PM, 2/10/2000, 8:25:00 AM, 3/22/2000, 2:51:00 PM, 4/30/2000, 8:07:00 PM, 6/10/2000, 3:52:00 PM, 8/20/2000, 4:18:00 AM, 10/30/2000, 2:44:00 PM, 1/9/2001, 9:36:00 PM, 4/21/2001, 11:14:00 AM, 7/30/2001, 5:04:00 PM, 11/8/2001, 1:43:00 PM, 3/21/2002, 6:05:00 AM, 7/29/2002, 3:04:00 PM, 12/8/2002, 1:45:00 PM, 5/20/2003, 5:44:00 PM, 10/28/2003, 6:50:00 PM, 4/8/2004, 1:56:00 PM, 10/18/2004, 1:06:00 PM, 4/29/2005, 10:38:00 PM, 11/7/2005, 9:18:00 AM, 6/19/2006, 4:24:00 PM, 1/27/2007, 11:14:00 PM, 9/8/2007, 4:51:00 PM, 5/18/2008, 12:45:00 PM, 1/26/2009, 12:13:00 PM, 10/8/2009, 1:33:00 AM, 7/18/2010, 3:17:00 AM, 4/27/2011, 12:12:00 PM, 2/5/2012, 7:09:00 PM, 12/17/2012, 12:29:00 AM, 10/27/2013, 2:12:00 AM, 9/6/2014, 1:34:00 AM, 8/17/2015, 5:55:00 PM, 7/26/2016, 6:19:00 AM, 7/6/2017, 1:39:00 PM, 7/16/2018, 9:21:00 AM, 7/26/2019, 10:15:00 PM, 8/4/2020, 11:31:00 AM, 9/15/2021, 1:32:00 AM, 10/26/2022, 2:06:00 PM, 12/5/2023, 6:58:00 AM, 2/13/2025, 6:05:00 PM, 4/27/2026, 10:10:00 PM, 7/5/2027, 8:57:00 AM, 10/13/2028, 7:29:00 AM, 1/24/2030, 3:51:00 AM, 5/6/2031, 9:12:00 AM */

javascript how to sort by date

2 Answers2