fixing the handling of null cell values for date columns. Should fix #193

CHANGELOG.md

+- 3.1.3 
+  - Adding JavascriptDate class that mimics the way the Javascript Date object is created. (I wanted to be able to copy and paste google's examples into addRows)
+  
 - 3.1.1 & 3.1.2
   - Adding back and repairing the Symfony Bundle
   

src/DataTables/Rows/Row.php

@@ -101,12 +101,15 @@ class Row implements \ArrayAccess, \JsonSerializable
         foreach ($valueArray as $index => $cellValue) {
             if ((bool) preg_match('/date|datetime|timeofday/', $columnTypes[$index]) === true) {
                 if (StringValue::isNonEmpty($cellValue) === false &&
-                    $cellValue instanceof Carbon === false
+                    $cellValue instanceof Carbon === false &&
+                    $cellValue !== null
                 ) {
                     throw new InvalidDate($cellValue);
                 }
-                if ($cellValue instanceof Carbon) {
+                if ($cellValue === null) {
+                    $rowData[] = new NullCell;
+                } else if ($cellValue instanceof Carbon) {
                     $rowData[] = new DateCell($cellValue);
                 } else {
                     if (isset($dateTimeFormat)) {

src/Support/JavascriptDate.php

@@ -35,7 +35,7 @@ class JavascriptDate extends Carbon
         if (isset($args[3]) === false) {
             $hour = $defaults['hour'];
             $minute = isset($args[4]) ? $args[4] : $defaults['minute'];
-            $second = isset($args[5]) ? $args[5] : $defaults['minute'];
+            $second = isset($args[5]) ? $args[5] : $defaults['second'];
         } else {
             $minute = isset($args[4]) ? $args[4] : 0;
             $second = isset($args[5]) ? $args[5] : 0;