#14 fix sorting with nulls

Author: arthurkushman

gigatables.php

@@ -32,7 +32,7 @@
 //    'desc' => '<input type="text" name="ttl" value="Test '.$i.'st row Test '.$i.'st row Test '.$i.'st row Test '.$i.'st row Test '.$i.'st row" /> ', 
         'info' => 'some info some info some info some info',
         'date' => date('H:i:s d:m:Y', time() - $i),
-        'field1' => ($i % 5 === 0) ? null : $i,
+        'field1' => ($i % 5 === 0) ? null : (($i % 6 === 0) ? 0 : $i),
         'field2' => $i + 1234,
         'field3' => $i + 12345,
     ];

src/js/jquery.gigatables.js

@@ -357,8 +357,9 @@
                             // ===========
                             if (sortingOrder === SORT_ASC_NUM) { // asc
                                 nJson.sort(function (a, b) {
-                                    a = (eval('a.' + cols[idx].data) === null) ? '' : eval('a.' + cols[idx].data) + '';
-                                    b = (eval('b.' + cols[idx].data) === null) ? '' : eval('b.' + cols[idx].data) + '';
+                                    var an = eval('a.' + cols[idx].data), bn = eval('b.' + cols[idx].data);
+                                    a = (an === null) ? '' : an + '';
+                                    b = (bn === null) ? '' : bn + '';
                                     if (check === 0) { // check just the 1st time
                                         if (isNaN(a - b)) {
                                             isNan = 1;
@@ -372,8 +373,9 @@
                                 });
                             } else { // desc
                                 nJson.sort(function (a, b) {
-                                    a = (eval('a.' + cols[idx].data) === null) ? '' : eval('a.' + cols[idx].data) + '';
-                                    b = (eval('b.' + cols[idx].data) === null) ? '' : eval('b.' + cols[idx].data) + '';
+                                    var an = eval('a.' + cols[idx].data), bn = eval('b.' + cols[idx].data);
+                                    a = (an === null) ? '' : an + '';
+                                    b = (bn === null) ? '' : bn + '';
                                     if (check === 0) { // check just the 1st time
                                         if (isNaN(a - b)) {
                                             isNan = 1;