[Form] defined default and added example CollectionType prototype_data option

HeahDude · HeahDude · commit 6f1577149d2d · 2016-04-09T15:57:45.000+02:00
diff --git a/reference/forms/types/collection.rst b/reference/forms/types/collection.rst
@@ -369,8 +369,23 @@ prototype_data
 
 **type**: ``mixed`` **default**: ``null``
 
-Allows you to specify data for the prototype. Each new row added will initially
-contain the data set by this option.
+Allows you to define a specific data for the prototype. Each new row added will
+initially contain the data set by this option.
+By default, the same data as defined with ``entry_options`` for other entries
+will be used.
+
+.. code-block:: php
+
+    use Symfony\Component\Form\Extension\Core\Type\CollectionType;
+    use Symfony\Component\Form\Extension\Core\Type\TextType;
+
+    $builder->add('tags', CollectionType::class, array(
+        'class' => \AppBundle\Entity\Tag::class,
+        'entry_type' => TextType::class,
+        'allow_add' => true,
+        'prototype' => true,
+        'prototype_data' => 'New Tag Placeholder',
+    ));
 
 prototype_name
 ~~~~~~~~~~~~~~
