diff --git a/packages/mindplot/src/components/CommandContext.js b/packages/mindplot/src/components/CommandContext.js
index 199058c1..af0db886 100644
--- a/packages/mindplot/src/components/CommandContext.js
+++ b/packages/mindplot/src/components/CommandContext.js
@@ -59,7 +59,7 @@ class CommandContext {
   /** */
   createModel() {
     const mindmap = this._designer.getMindmap();
-    return mindmap.createNode(NodeModel.MAIN_TOPIC_TYPE);
+    return mindmap.createNode('MainTopic');
   }
 
   /** */
diff --git a/packages/mindplot/src/components/ConnectionLine.js b/packages/mindplot/src/components/ConnectionLine.js
index dcd4de45..3c3516f9 100644
--- a/packages/mindplot/src/components/ConnectionLine.js
+++ b/packages/mindplot/src/components/ConnectionLine.js
@@ -34,7 +34,7 @@ class ConnectionLine {
 
     let line;
     const ctrlPoints = this._getCtrlPoints(sourceNode, targetNode);
-    if (targetNode.getType() === INodeModel.CENTRAL_TOPIC_TYPE) {
+    if (targetNode.getType() === 'CentralTopic') {
       line = this._createLine(lineType, ConnectionLine.CURVED);
       line.setSrcControlPoint(ctrlPoints[0]);
       line.setDestControlPoint(ctrlPoints[1]);
diff --git a/packages/mindplot/src/components/Designer.js b/packages/mindplot/src/components/Designer.js
index cfb2a39d..142fb986 100644
--- a/packages/mindplot/src/components/Designer.js
+++ b/packages/mindplot/src/components/Designer.js
@@ -243,7 +243,7 @@ class Designer extends Events {
       });
 
       // Register node listeners ...
-      if (topic.getType() !== INodeModel.CENTRAL_TOPIC_TYPE) {
+      if (topic.getType() !== 'CentralTopic') {
         // Central Topic doesn't support to be dragged
         this._dragManager.add(topic);
       }
@@ -443,7 +443,7 @@ class Designer extends Events {
     }
     // Execute event ...
     const topic = nodes[0];
-    if (topic.getType() !== INodeModel.CENTRAL_TOPIC_TYPE) {
+    if (topic.getType() !== 'CentralTopic') {
       this._actionDispatcher.shrinkBranch([topic.getId()], !topic.areChildrenShrunken());
     }
   }
@@ -476,7 +476,7 @@ class Designer extends Events {
        */
   _copyNodeProps(sourceModel, targetModel) {
     // I don't copy the font size if the target is the source is the central topic.
-    if (sourceModel.getType() !== INodeModel.CENTRAL_TOPIC_TYPE) {
+    if (sourceModel.getType() !== 'CentralTopic') {
       const fontSize = sourceModel.getFontSize();
       if (fontSize) {
         targetModel.setFontSize(fontSize);
@@ -586,7 +586,7 @@ class Designer extends Events {
 
       // Hack: if parent is central topic, add node below not on opposite side.
       // This should be done in the layout
-      if (parentTopic.getType() === INodeModel.CENTRAL_TOPIC_TYPE) {
+      if (parentTopic.getType() === 'CentralTopic') {
         siblingModel.setOrder(topic.getOrder() + 2);
       }
 
@@ -954,7 +954,7 @@ class Designer extends Events {
   /** */
   changeTopicShape(shape) {
     const validateFunc = (topic) => !(
-      topic.getType() === INodeModel.CENTRAL_TOPIC_TYPE && shape === TopicShape.LINE
+      topic.getType() === 'CentralTopic' && shape === TopicShape.LINE
     );
 
     const validateError = 'Central Topic shape can not be changed to line figure.';
diff --git a/packages/mindplot/src/components/DragPivot.js b/packages/mindplot/src/components/DragPivot.js
index 8f6f345a..bebe5e3a 100644
--- a/packages/mindplot/src/components/DragPivot.js
+++ b/packages/mindplot/src/components/DragPivot.js
@@ -145,7 +145,7 @@ class DragPivot {
     let result = null;
     const parentTopic = this._targetTopic;
     if (parentTopic) {
-      if (parentTopic.getType() === INodeModel.CENTRAL_TOPIC_TYPE) {
+      if (parentTopic.getType() === 'CentralTopic') {
         result = this._straightLine;
       } else {
         result = this._curvedLine;
diff --git a/packages/mindplot/src/components/IconGroup.js b/packages/mindplot/src/components/IconGroup.js
index e66f4f02..2ba1f39f 100644
--- a/packages/mindplot/src/components/IconGroup.js
+++ b/packages/mindplot/src/components/IconGroup.js
@@ -25,15 +25,12 @@ import {
 } from '@wisemapping/web2d';
 import IconGroupRemoveTip from './IconGroupRemoveTip';
 
-import NoteModel from './model/NoteModel';
-import LinkModel from './model/LinkModel';
-import IconModel from './model/IconModel';
 import Icon from './Icon';
 
 const ORDER_BY_TYPE = new Map();
-ORDER_BY_TYPE.set(IconModel.FEATURE_TYPE, 0);
-ORDER_BY_TYPE.set(NoteModel.FEATURE_TYPE, 1);
-ORDER_BY_TYPE.set(LinkModel.FEATURE_TYPE, 2);
+ORDER_BY_TYPE.set('icon', 0);
+ORDER_BY_TYPE.set('note', 1);
+ORDER_BY_TYPE.set('link', 2);
 
 class IconGroup {
   constructor(topicId, iconSize) {
@@ -191,4 +188,4 @@ class IconGroup {
 }
 
 IconGroup.ICON_PADDING = 5;
-export default IconGroup;
\ No newline at end of file
+export default IconGroup;
diff --git a/packages/mindplot/src/components/NodeGraphUtils.js b/packages/mindplot/src/components/NodeGraphUtils.js
index 30ec6aa2..d5a4ca1b 100644
--- a/packages/mindplot/src/components/NodeGraphUtils.js
+++ b/packages/mindplot/src/components/NodeGraphUtils.js
@@ -22,9 +22,9 @@ export const create = (nodeModel, options) => {
   $assert(type, 'Node model type can not be null');
 
   let result;
-  if (type === INodeModel.CENTRAL_TOPIC_TYPE) {
+  if (type === 'CentralTopic') {
     result = new CentralTopic(nodeModel, options);
-  } else if (type === INodeModel.MAIN_TOPIC_TYPE) {
+  } else if (type === 'MainTopic') {
     result = new MainTopic(nodeModel, options);
   } else {
     $assert(false, `unsupported node type:${type}`);
diff --git a/packages/mindplot/src/components/Relationship.js b/packages/mindplot/src/components/Relationship.js
index d810f3c1..68d6d3e9 100644
--- a/packages/mindplot/src/components/Relationship.js
+++ b/packages/mindplot/src/components/Relationship.js
@@ -86,7 +86,7 @@ class Relationship extends ConnectionLine {
 
     const targetTopic = this._targetTopic;
     let targetPosition = targetTopic.getPosition();
-    if (targetTopic.getType() === INodeModel.CENTRAL_TOPIC_TYPE) {
+    if (targetTopic.getType() === 'CentralTopic') {
       targetPosition = Shape.workoutIncomingConnectionPoint(targetTopic, sourcePosition);
     }
 
diff --git a/packages/mindplot/src/components/RelationshipPivot.js b/packages/mindplot/src/components/RelationshipPivot.js
index 88b84606..50f02f23 100644
--- a/packages/mindplot/src/components/RelationshipPivot.js
+++ b/packages/mindplot/src/components/RelationshipPivot.js
@@ -131,7 +131,7 @@ class RelationshipPivot {
   _calculateFromPosition(toPosition) {
     // Calculate origin position ...
     let sourcePosition = this._sourceTopic.getPosition();
-    if (this._sourceTopic.getType() === INodeModel.CENTRAL_TOPIC_TYPE) {
+    if (this._sourceTopic.getType() === 'CentralTopic') {
       sourcePosition = Shape.workoutIncomingConnectionPoint(this._sourceTopic, toPosition);
     }
     const controlPoint = Shape.calculateDefaultControlPoints(sourcePosition, toPosition);
diff --git a/packages/mindplot/src/components/Topic.js b/packages/mindplot/src/components/Topic.js
index 834bf966..a298bfbc 100644
--- a/packages/mindplot/src/components/Topic.js
+++ b/packages/mindplot/src/components/Topic.js
@@ -1337,7 +1337,7 @@ class Topic extends NodeGraph {
 
   /** @return {Boolean} true if the topic is the central topic of the map */
   isCentralTopic() {
-    return this.getModel().getType() === INodeModel.CENTRAL_TOPIC_TYPE;
+    return this.getModel().getType() === 'CentralTopic';
   }
 }
 
diff --git a/packages/mindplot/src/components/TopicFeature.js b/packages/mindplot/src/components/TopicFeature.js
index d7186010..59161426 100644
--- a/packages/mindplot/src/components/TopicFeature.js
+++ b/packages/mindplot/src/components/TopicFeature.js
@@ -17,29 +17,26 @@
  */
 
 import { $assert } from '@wisemapping/core-js';
-import IconModel from './model/IconModel';
 import ImageIcon from './ImageIcon';
-import LinkModel from './model/LinkModel';
 import LinkIcon from './LinkIcon';
-import NoteModel from './model/NoteModel';
 import NoteIcon from './NoteIcon';
 
 const TopicFeatureFactory = {
   /** the icon object */
   Icon: {
-    id: IconModel.FEATURE_TYPE,
+    id: 'icon',
     icon: ImageIcon,
   },
 
   /** the link object */
   Link: {
-    id: LinkModel.FEATURE_TYPE,
+    id: 'link',
     icon: LinkIcon,
   },
 
   /** the note object */
   Note: {
-    id: NoteModel.FEATURE_TYPE,
+    id: 'note',
     icon: NoteIcon,
   },
 
diff --git a/packages/mindplot/src/components/persistence/XMLSerializerBeta.js b/packages/mindplot/src/components/persistence/XMLSerializerBeta.js
index 05562ea1..fd8f044c 100644
--- a/packages/mindplot/src/components/persistence/XMLSerializerBeta.js
+++ b/packages/mindplot/src/components/persistence/XMLSerializerBeta.js
@@ -51,11 +51,11 @@ class XMLSerializerBeta {
     const parentTopic = document.createElement('topic');
 
     // Set topic attributes...
-    if (topic.getType() === INodeModel.CENTRAL_TOPIC_TYPE) {
+    if (topic.getType() === 'CentralTopic') {
       parentTopic.setAttribute('central', true);
     } else {
       const parent = topic.getParent();
-      if (parent == null || parent.getType() === INodeModel.CENTRAL_TOPIC_TYPE) {
+      if (parent == null || parent.getType() === 'CentralTopic') {
         const pos = topic.getPosition();
         parentTopic.setAttribute('position', `${pos.x},${pos.y}`);
       } else {
@@ -206,8 +206,8 @@ class XMLSerializerBeta {
 
   _deserializeNode(domElem, mindmap) {
     const type = domElem.getAttribute('central') != null
-      ? INodeModel.CENTRAL_TOPIC_TYPE
-      : INodeModel.MAIN_TOPIC_TYPE;
+      ? 'CentralTopic'
+      : 'MainTopic';
     const topic = mindmap.createNode(type);
 
     // Load attributes...
diff --git a/packages/mindplot/src/components/persistence/XMLSerializerPela.js b/packages/mindplot/src/components/persistence/XMLSerializerPela.js
index af9dabdd..d3796f37 100644
--- a/packages/mindplot/src/components/persistence/XMLSerializerPela.js
+++ b/packages/mindplot/src/components/persistence/XMLSerializerPela.js
@@ -68,7 +68,7 @@ class XMLSerializerPela {
     const parentTopic = document.createElement('topic');
 
     // Set topic attributes...
-    if (topic.getType() === INodeModel.CENTRAL_TOPIC_TYPE) {
+    if (topic.getType() === 'CentralTopic') {
       parentTopic.setAttribute('central', 'true');
     } else {
       const pos = topic.getPosition();
@@ -96,7 +96,7 @@ class XMLSerializerPela {
       }
     }
 
-    if (topic.areChildrenShrunken() && topic.getType() !== INodeModel.CENTRAL_TOPIC_TYPE) {
+    if (topic.areChildrenShrunken() && topic.getType() !== 'CentralTopic') {
       parentTopic.setAttribute('shrink', 'true');
     }
 
@@ -268,8 +268,8 @@ class XMLSerializerPela {
 
   _deserializeNode(domElem, mindmap) {
     const type = domElem.getAttribute('central') != null
-      ? INodeModel.CENTRAL_TOPIC_TYPE
-      : INodeModel.MAIN_TOPIC_TYPE;
+      ? 'CentralTopic'
+      : 'MainTopic';
 
     // Load attributes...
     let id = domElem.getAttribute('id');
@@ -349,7 +349,7 @@ class XMLSerializerPela {
 
     const isShrink = domElem.getAttribute('shrink');
     // Hack: Some production maps has been stored with the central topic collapsed. This is a bug.
-    if ($defined(isShrink) && type !== INodeModel.CENTRAL_TOPIC_TYPE) {
+    if ($defined(isShrink) && type !== 'CentralTopic') {
       topic.setChildrenShrunken(isShrink);
     }