FEATURE: Create Mixin for Placeholder-Insert

- Create a Mixin by which Form-Elements are shown in the placeholder insert
- Load all form-elements recursively
- Check if the elements are allowed to shown in the Placeholder-Insert-Dropdown
   by checking if they have the PlaceholderInsert-Mixin.

Resolves: neos#99

Configuration/NodeTypes.FormElement.yaml

@@ -6,6 +6,7 @@
     'Neos.Form.Builder:LabelMixin': true
     'Neos.Form.Builder:DefaultValueMixin': true
     'Neos.Form.Builder:RequiredCheckboxMixin': true
+    'Neos.Form.Builder:Mixin.PlaceholderInsert': true
   constraints:
     nodeTypes:
       '*': false

Configuration/NodeTypes.FormElements.Section.yaml

@@ -5,6 +5,7 @@
     'Neos.Form.Builder:IdentifierMixin': false
     'Neos.Form.Builder:DefaultValueMixin': false
     'Neos.Form.Builder:RequiredCheckboxMixin': false
+    'Neos.Form.Builder:Mixin.PlaceholderInsert': false
   ui:
     label: 'Section'
     icon: 'icon-folder-open'

Configuration/NodeTypes.FormElements.StaticText.yaml

@@ -4,6 +4,7 @@
     'Neos.Form.Builder:IdentifierMixin': false
     'Neos.Form.Builder:DefaultValueMixin': false
     'Neos.Form.Builder:RequiredCheckboxMixin': false
+    'Neos.Form.Builder:Mixin.PlaceholderInsert': false
   ui:
     label: 'Static text'
     icon: 'icon-align-left'

Configuration/NodeTypes.Mixin.PaceholderInsert.yaml

@@ -0,0 +1,2 @@
+'Neos.Form.Builder:Mixin.PlaceholderInsert':
+  abstract: true

README.md

@@ -381,3 +381,15 @@ selectable:
         }
     }
 ```
+
+## Example: Allow specific NodeTypes in the Placeholder-Insert
+
+By default, all Form-Element NodeTypes are visible in the Placeholder-Insert (except StaticText and Section).
+
+If you want to hide specific Form-Elements from the Placeholder-Insert then just disable the superType.
+
+```yaml
+'FooBar.Form.Builder:Element.HiddenInInset':
+  superTypes:
+    'Neos.Form.Builder:Mixin.PlaceholderInsert': false
+```

Resources/Private/PlaceholderInsert/src/PlaceholderInsertDropdown.js

@@ -32,6 +32,7 @@ export const parentNodeContextPath = contextPath => {
     "@neos-project/neos-ui-contentrepository"
   )
 }))
+
 export default class PlaceholderInsertDropdown extends PureComponent {
   handleOnSelect = value => {
     this.props.executeCommand("placeholderInsert", value);
@@ -48,13 +49,7 @@ export default class PlaceholderInsertDropdown extends PureComponent {
     if (!elementsNode) {
       return null;
     }
-    const options = elementsNode.children
-      .map(node => this.props.nodesByContextPath[node.contextPath])
-      .map(node => ({
-        value: node.properties.identifier || node.identifier,
-        label:
-          node.properties.label || node.properties.identifier || node.identifier
-      }));
+    const options = this.getOptionsRecursively(elementsNode.children);
 
     if (options.length === 0) {
       return null;
@@ -74,4 +69,33 @@ export default class PlaceholderInsertDropdown extends PureComponent {
       />
     );
   }
+
+  getOptionsRecursively(elements) {
+    const {nodeTypeRegistry} = this.props;
+    const returnValues = [];
+
+
+    elements.forEach((element) => {
+      const node = this.props.nodesByContextPath[element.contextPath];
+      const childNodes = this.props.nodesByContextPath[element.contextPath].children;
+
+      if (nodeTypeRegistry.isOfType(node.nodeType, 'Neos.Form.Builder:Mixin.PlaceholderInsert')) {
+        returnValues.push({
+          value: node.properties.identifier || node.identifier,
+          label:
+            node.properties.label || node.properties.identifier || node.identifier
+        });
+      }
+
+      const childOptions = this.getOptionsRecursively(childNodes);
+
+      if (Array.isArray(childOptions)) {
+        childOptions.forEach(childOption => {
+          returnValues.push(childOption);
+        });
+      }
+    });
+
+    return returnValues;
+  }
 }