Add new methods for Displayed

Author: hailwood

code/DataListExtension.php

@@ -5,10 +5,38 @@
  *
  * @property DataList owner
  */
-class DataListExtension extends Extension {
+class DataListExtension extends Extension
+{
 
-	public function ListColumn($column, $glue = ', '){
-		return implode($glue, $this->owner->column($column));
-	}
+    public function ListColumn($column, $glue = ', ')
+    {
+        return implode($glue, $this->owner->column($column));
+    }
 
-}
+    public function Displayed($visible = true)
+    {
+        $list = clone $this->owner;
+
+        return $list->filter('Displayed', $visible);
+    }
+
+    public function OnlyVisible()
+    {
+        return $this->Displayed(true);
+    }
+
+    public function OnlyHidden()
+    {
+        return $this->Displayed(false);
+    }
+
+    public function WithVisible($relation)
+    {
+        $list = clone $this->owner;
+
+        return $list->filterByCallback(function ($obj) use ($relation) {
+            return $obj->{$relation}()->OnlyVisible()->exists();
+        });
+    }
+
+}