Question

When soritng an array made of a mix of strings, null values and zeros, i get the result not properly as exptected, null values seem to get sorted as if they were ‘null’ strings.
I did this (tested on FireFox):

var arr1 = arr2 = [null, "b", "c", "d", null, "e", 0, "g", null, 0, "h", "i", "l", "m", "n", "o", "p", "ne", "nur", "nimbus"];

document.write("SORTED ARRAY:<br>");
arr1.sort();
arr1.forEach(function(val){document.write(val + "; ")});

And the result is:

SORTED ARRAY:
0; 0; b; c; d; e; g; h; i; l; m; n; ne; nimbus; null; null; null; nur; o; p;

Do you have an idea of how to make the null value be considered like empty string during the sorting of the array, so that they appear 1st in the sorted arry along with the zeros.

Thanks!

Answer 1

This will do what you want by converting everything to strings (in particular converting null to an empty string) and allowing JavaScript’s built-in string comparison do the work:

arr2.sort( function(a, b) 
{
    /* 
       We avoid reuse of arguments variables in a sort
       comparison function because of a bug in IE <= 8.
       See http://www.zachleat.com/web/array-sort/
    */
    var va = (a === null) ? "" : "" + a,
        vb = (b === null) ? "" : "" + b;

    return va > vb ? 1 : ( va === vb ? 0 : -1 );
} );