Decoding the date sorting in Javascript, efficient faster and native way.

Coming from the previous post ( http://www.developerscloud.org/2014/05/decoding-underscore-js-sortby-sorting.html),  where we have used the underscore to sort the array, with the limitation of sorting in descending order, I will show you in below post how to sort effectively using javascript native functionality.

Lets use the same array we have in the previous post.

var datesArray = ['6-01-2014','2-01-2014', '4-01-2014', '5-01-2014', '3-01-2014', '1-01-2014'];

datesArray is now

["6-01-2014", "2-01-2014", "4-01-2014", "5-01-2014", "3-01-2014", "1-01-2014"]

Running the for loop making each item of array a date type object.

for(var i = 0; i< datesArray.length; i++){

datesArray[i] = new Date(datesArray [i]);

}

After which datesArray will become

[Sun Jun 01 2014 00:00:00 GMT+0530 (India Standard Time),

Sat Feb 01 2014 00:00:00 GMT+0530 (India Standard Time),

Tue Apr 01 2014 00:00:00 GMT+0530 (India Standard Time),

Thu May 01 2014 00:00:00 GMT+0530 (India Standard Time),

Sat Mar 01 2014 00:00:00 GMT+0530 (India Standard Time),

Wed Jan 01 2014 00:00:00 GMT+0530 (India Standard Time)]

// below are the comparison function that will result in dates being sorted in

// ASCENDING & DESCENDING order. As you can see, JavaScript's native comparison operators

// can be used to compare dates. Avoiding the use of sort by of underscore.

//Descending 

var date_sort_desc = function (date1, date2) {

       if (date1 > date2) return -1;

       if (date1 < date2) return 1;

       return 0;

 };

//Ascending

var date_sort_asc = function (date1, date2) {

if (date1 > date2) return 1;

if (date1 < date2) return -1;

return 0;

 };

Output:

datesArray.sort(date_sort_desc);

[Sun Jun 01 2014 00:00:00 GMT+0530 (India Standard Time),

Thu May 01 2014 00:00:00 GMT+0530 (India Standard Time),

Tue Apr 01 2014 00:00:00 GMT+0530 (India Standard Time),

Sat Mar 01 2014 00:00:00 GMT+0530 (India Standard Time),

Sat Feb 01 2014 00:00:00 GMT+0530 (India Standard Time),

Wed Jan 01 2014 00:00:00 GMT+0530 (India Standard Time)]

datesArray.sort(date_sort_asc);

[Wed Jan 01 2014 00:00:00 GMT+0530 (India Standard Time),

 Sat Feb 01 2014 00:00:00 GMT+0530 (India Standard Time),

 Sat Mar 01 2014 00:00:00 GMT+0530 (India Standard Time),

 Tue Apr 01 2014 00:00:00 GMT+0530 (India Standard Time),

 Thu May 01 2014 00:00:00 GMT+0530 (India Standard Time),

 Sun Jun 01 2014 00:00:00 GMT+0530 (India Standard Time)]

Converting back the array into the original format of dates.

for(var i = 0; i<x.length;i++){

datesArray[i] = datesArray[i].toISOString().slice(0, 10);

}

The formatted output result. 

datesArray

["2013-12-31", "2014-01-31", "2014-02-28", "2014-03-31", "2014-04-30", "2014-05-31"]

I hope you will all find it helpful.