fix: fix requireIf checked and notChecked conditional key implementations

This fix now considers when the checkbox field is sent, in the case of api requests. Web browsers do
not send unchecked checkbox fields

Author: Harrison Ifeanyichukwu

src/Handler.php

@@ -361,6 +361,21 @@ protected function validateFields(array $fields, bool $required)
         }
     }
 
+    /**
+     * tests if a value is falsy
+     *
+     *@param $value - the value to test
+    */
+    protected function valueIsFalsy($value)
+    {
+        $value = strval($value);
+
+        if (preg_match('/^(false|off|0|nil|null|no|undefined)$/i', $value) || $value === '')
+            return true;
+        else
+            return false;
+    }
+
     /**
      * runs data filteration on the given value
      *
@@ -425,7 +440,7 @@ protected function filterValue($value, array $filters)
                 break;
 
             case 'bool':
-                if (preg_match('/^(false|off|0|nil|null|no|undefined)$/i', $value) || $value === '')
+                if ($this->valueIsFalsy($value))
                     $value = false;
                 else
                     $value = true;
@@ -699,12 +714,12 @@ protected function processRules()
                 switch(strtolower($condition))
                 {
                     case 'checked':
-                        if (!is_null($_field_value))
+                        if (!$this->valueIsFalsy($_field_value))
                             $required = true;
                         break;
 
                     case 'notchecked':
-                        if (is_null($_field_value))
+                        if ($this->valueIsFalsy($_field_value))
                             $required = true;
                         break;