chore(modeling): do not expose ElementFactory helpers

Less API surface => BETTER.

lib/features/modeling/ElementFactory.js

@@ -81,7 +81,7 @@ ElementFactory.prototype.createBpmnElement = function(elementType, attrs) {
     delete attrs.colors;
   }
 
-  this.setAttrs(businessObject, attrs, [
+  applyAttributes(businessObject, attrs, [
     'processRef',
     'isInterrupting',
     'associationDirection',
@@ -89,7 +89,7 @@ ElementFactory.prototype.createBpmnElement = function(elementType, attrs) {
   ]);
 
   if (attrs.isExpanded) {
-    this.setAttr(businessObject.di, attrs, 'isExpanded');
+    applyAttribute(businessObject.di, attrs, 'isExpanded');
   }
 
   if (is(businessObject, 'bpmn:ExclusiveGateway')) {
@@ -122,23 +122,6 @@ ElementFactory.prototype.createBpmnElement = function(elementType, attrs) {
 };
 
 
-ElementFactory.prototype.setAttrs = function(element, attrs, properties) {
-
-  forEach(properties, function(property) {
-    if (attrs[property] !== undefined) {
-      this.setAttr(element, attrs, property);
-    }
-  }, this);
-};
-
-
-ElementFactory.prototype.setAttr = function(element, attrs, property) {
-  element[property] = attrs[property];
-
-  delete attrs[property];
-};
-
-
 ElementFactory.prototype._getDefaultSize = function(semantic) {
 
   if (is(semantic, 'bpmn:SubProcess')) {
@@ -200,3 +183,37 @@ ElementFactory.prototype.createParticipantShape = function(collapsed) {
 
   return this.createShape(attrs);
 };
+
+
+//////////// helpers ////////////////////////////////////
+
+/**
+ * Apply attributes from a map to the given element,
+ * remove attribute from the map on application.
+ *
+ * @param {Base} element
+ * @param {Object} attrs (in/out map of attributes)
+ * @param {Array<String>} attributeNames name of attributes to apply
+ */
+function applyAttributes(element, attrs, attributeNames) {
+
+  forEach(attributeNames, function(property) {
+    if (attrs[property] !== undefined) {
+      applyAttribute(element, attrs, property);
+    }
+  });
+}
+
+/**
+ * Apply named property to element and drain it from the attrs
+ * collection.
+ *
+ * @param {Base} element
+ * @param {Object} attrs (in/out map of attributes)
+ * @param {String} attributeName to apply
+ */
+function applyAttribute(element, attrs, attributeName) {
+  element[attributeName] = attrs[attributeName];
+
+  delete attrs[attributeName];
+}