diff --git a/packages/mindplot/src/components/export/TxtExporter.ts b/packages/mindplot/src/components/export/TxtExporter.ts
index 192aca54..b083208d 100644
--- a/packages/mindplot/src/components/export/TxtExporter.ts
+++ b/packages/mindplot/src/components/export/TxtExporter.ts
@@ -16,6 +16,8 @@
  *   limitations under the License.
  */
 import { Mindmap } from "../..";
+import INodeModel from "../model/INodeModel";
+import LinkModel from "../model/LinkModel";
 import NodeModel from "../model/NodeModel";
 import Exporter from "./Exporter";
 
@@ -37,12 +39,15 @@ class TxtExporter implements Exporter {
         return Promise.resolve(retult);
     }
 
-    private traverseBranch(prefix: string, branches: Array<NodeModel>) {
+    private traverseBranch(prefix: string, branches: Array<INodeModel>) {
         let result = '';
         branches.forEach((node, index) => {
             result = result + `${prefix}${index+1} ${node.getText()}`;
             node.getFeatures().forEach((f)=>{
-                    
+                const type = f.getType();
+                if(type === 'link'){
+                    result = result + ` [link: ${(f as LinkModel).getUrl}]`
+                }    
             });
             result = result + '\n';
 
diff --git a/packages/mindplot/src/components/model/FeatureModel.js b/packages/mindplot/src/components/model/FeatureModel.ts
similarity index 84%
rename from packages/mindplot/src/components/model/FeatureModel.js
rename to packages/mindplot/src/components/model/FeatureModel.ts
index 6a5aa494..8e296a0a 100644
--- a/packages/mindplot/src/components/model/FeatureModel.js
+++ b/packages/mindplot/src/components/model/FeatureModel.ts
@@ -15,16 +15,23 @@
  *   See the License for the specific language governing permissions and
  *   limitations under the License.
  */
-import { $assert, $defined } from '@wisemapping/core-js';
+import { $assert } from '@wisemapping/core-js';
+
+export type FeatureType = 'note' | 'link' | 'icon';
 
 class FeatureModel {
+  static _next_id = 0;
+  _id: number;
+  _type: FeatureType;
+  _attributes: {};
+
   /**
      * @constructs
      * @param type
      * @throws will throw an exception if type is null or undefined
      * assigns a unique id and the given type to the new model
      */
-  constructor(type) {
+  constructor(type: FeatureType) {
     $assert(type, 'type can not be null');
     this._id = FeatureModel._nextUUID();
 
@@ -77,19 +84,15 @@ class FeatureModel {
     this._id = id;
   }
 
-  /** */
-  getType() {
+  getType(): FeatureType {
     return this._type;
   }
+
+  static _nextUUID(): number {
+    const result = FeatureModel._next_id + 1;
+    FeatureModel._next_id = result;
+    return result;
+  }
 }
 
-FeatureModel._nextUUID = function _nextUUID() {
-  if (!$defined(FeatureModel._uuid)) {
-    FeatureModel._uuid = 0;
-  }
-
-  FeatureModel._uuid += 1;
-  return FeatureModel._uuid;
-};
-
 export default FeatureModel;
diff --git a/packages/mindplot/src/components/model/FeatureModelFactory.ts b/packages/mindplot/src/components/model/FeatureModelFactory.ts
index 8f871c09..654b94b3 100644
--- a/packages/mindplot/src/components/model/FeatureModelFactory.ts
+++ b/packages/mindplot/src/components/model/FeatureModelFactory.ts
@@ -2,20 +2,25 @@ import { $assert } from '@wisemapping/core-js';
 import IconModel from './IconModel';
 import LinkModel from './LinkModel';
 import NoteModel from './NoteModel';
-import FeatureModel from './FeatureModel';
+import FeatureModel, { FeatureType } from './FeatureModel';
+
+
+interface NodeById {
+  id: FeatureType,
+  model: typeof FeatureModel;
+}
 
 class FeatureModelFactory {
-
-  private static modelById = [{
-    id: IconModel.FEATURE_TYPE,
+  static modelById: Array<NodeById> = [{
+    id: 'icon',
     model: IconModel,
   }, {
-    id: LinkModel.FEATURE_TYPE,
+    id: 'link',
     model: LinkModel,
   }, {
-    id: NoteModel.FEATURE_TYPE,
+    id: 'note',
     model: NoteModel,
-  }] as const;
+  }];
 
   static createModel(type: string, attributes): FeatureModel {
     $assert(type, 'type can not be null');
diff --git a/packages/mindplot/src/components/model/IMindmap.ts b/packages/mindplot/src/components/model/IMindmap.ts
index 3533554d..56c3ed07 100644
--- a/packages/mindplot/src/components/model/IMindmap.ts
+++ b/packages/mindplot/src/components/model/IMindmap.ts
@@ -18,35 +18,36 @@
  *   limitations under the License.
  */
 import { $assert } from '@wisemapping/core-js';
+import INodeModel, { NodeModelType as NodeType } from './INodeModel';
 import NodeModel from './NodeModel';
 import RelationshipModel from './RelationshipModel';
 
 abstract class IMindmap {
-  getCentralTopic(): NodeModel {
+  getCentralTopic(): INodeModel {
     return this.getBranches()[0];
   }
 
   abstract getDescription(): string;
 
-  abstract setDescription(value: string);
+  abstract setDescription(value: string): void;
 
   abstract getId(): string
 
-  abstract setId(id: string);
+  abstract setId(id: string): void;
 
   abstract getVersion(): string;
 
   abstract setVersion(version: string): void;
 
-  abstract addBranch(nodeModel: NodeModel): void;
+  abstract addBranch(nodeModel: INodeModel): void;
 
-  abstract getBranches(): Array<NodeModel>;
+  abstract getBranches(): Array<INodeModel>;
 
-  abstract removeBranch(node: NodeModel): void;
+  abstract removeBranch(node: INodeModel): void;
 
   abstract getRelationships(): Array<RelationshipModel>;
 
-  connect(parent: NodeModel, child: NodeModel): void {
+  connect(parent: INodeModel, child: INodeModel): void {
     // Child already has a parent ?
     $assert(!child.getParent(), 'Child model seems to be already connected');
 
@@ -62,7 +63,7 @@ abstract class IMindmap {
      * @throws will throw an error if child is null or undefined
      * @throws will throw an error if child's parent cannot be found
      */
-  disconnect(child: NodeModel): void {
+  disconnect(child: INodeModel): void {
     const parent = child.getParent();
     $assert(child, 'Child can not be null.');
     $assert(parent, 'Child model seems to be already connected');
@@ -71,23 +72,15 @@ abstract class IMindmap {
     this.addBranch(child);
   }
 
-  /** @abstract */
-  hasAlreadyAdded(node) {
-    throw new Error('Unsupported operation');
-  }
+  abstract hasAlreadyAdded(node: INodeModel): boolean;
 
-  /** @abstract */
-  createNode(type, id) {
-    throw new Error('Unsupported operation');
-  }
+  abstract  createNode(type: NodeType, id: number):void;
 
   abstract createRelationship(fromNode: NodeModel, toNode: NodeModel): void;
 
   abstract addRelationship(rel: RelationshipModel): void;
 
-  deleteRelationship(relationship: RelationshipModel): void {
-    throw new Error('Unsupported operation');
-  }
+  abstract deleteRelationship(relationship: RelationshipModel): void;
 
   /** */
   inspect() {
diff --git a/packages/mindplot/src/components/model/INodeModel.js b/packages/mindplot/src/components/model/INodeModel.ts
similarity index 79%
rename from packages/mindplot/src/components/model/INodeModel.js
rename to packages/mindplot/src/components/model/INodeModel.ts
index dbaa4fe9..a086ce2e 100644
--- a/packages/mindplot/src/components/model/INodeModel.js
+++ b/packages/mindplot/src/components/model/INodeModel.ts
@@ -17,47 +17,53 @@
  *   limitations under the License.
  */
 import { $assert, $defined } from '@wisemapping/core-js';
+import FeatureModel from './FeatureModel';
+import Mindmap from './Mindmap';
 
 // regex taken from https://stackoverflow.com/a/34763398/58128
-const parseJsObject = (str) => JSON.parse(str.replace(/(['"])?([a-z0-9A-Z_]+)(['"])?:/g, '"$2": '));
+const parseJsObject = (str: string) => JSON.parse(str.replace(/(['"])?([a-z0-9A-Z_]+)(['"])?:/g, '"$2": '));
 
-class INodeModel {
-  constructor(mindmap) {
+abstract class INodeModel {
+  static MAIN_TOPIC_TO_MAIN_TOPIC_DISTANCE: number = 220;
+  static _next_uuid: number = 0;
+
+  _mindmap: Mindmap;
+
+  constructor(mindmap: Mindmap) {
     $assert(mindmap && mindmap.getBranches, 'mindmap can not be null');
     this._mindmap = mindmap;
   }
 
-  /** */
-  getId() {
+  getId(): number {
     return this.getProperty('id');
   }
+  abstract getFeatures(): Array<FeatureModel>;
 
   /** */
-  setId(id) {
+  setId(id: number): void {
     if (!$defined(id)) {
       const newId = INodeModel._nextUUID();
       this.putProperty('id', newId);
     } else {
-      if (id > INodeModel._uuid) {
+      if (id > INodeModel._next_uuid) {
         $assert(Number.isFinite(id));
-        INodeModel._uuid = id;
+        INodeModel._next_uuid = id;
       }
       this.putProperty('id', id);
     }
   }
 
-  /** */
-  getType() {
+  getType(): NodeModelType {
     return this.getProperty('type');
   }
 
   /** */
-  setType(type) {
+  setType(type: NodeModelType): void {
     this.putProperty('type', type);
   }
 
   /** */
-  setText(text) {
+  setText(text: string): void {
     this.putProperty('text', text);
   }
 
@@ -315,39 +321,55 @@ class INodeModel {
     //        console.log("After:" + mindmap.inspect());
   }
 
-  /** @abstract */
-  getPropertiesKeys() {
-    throw new Error('Unsupported operation');
+  abstract getPropertiesKeys(): string[];
+
+  abstract getProperty(key: string);
+
+  abstract putProperty(key: string, value: any): void;
+
+  abstract setParent(parent: INodeModel): void;
+
+  abstract getChildren(): INodeModel[];
+
+  abstract getParent(): INodeModel;
+
+  abstract clone(): INodeModel;
+
+  isChildNode(node: INodeModel): boolean {
+    let result = false;
+    if (node === this) {
+      result = true;
+    } else {
+      const children = this.getChildren();
+      for (let i = 0; i < children.length; i++) {
+        const child = children[i];
+        result = child.isChildNode(node);
+        if (result) {
+          break;
+        }
+      }
+    }
+    return result;
   }
 
-  /** @abstract */
-  // eslint-disable-next-line no-unused-vars
-  putProperty(key, value) {
-    throw new Error('Unsupported operation');
+  findNodeById(id: number): INodeModel {
+    $assert(Number.isFinite(id));
+    let result = null;
+    if (this.getId() === id) {
+      result = this;
+    } else {
+      const children = this.getChildren();
+      for (let i = 0; i < children.length; i++) {
+        const child = children[i];
+        result = child.findNodeById(id);
+        if (result) {
+          break;
+        }
+      }
+    }
+    return result;
   }
 
-  /** @abstract */
-  // eslint-disable-next-line no-unused-vars
-  setParent(parent) {
-    throw new Error('Unsupported operation');
-  }
-
-  /** @abstract */
-  getChildren() {
-    throw new Error('Unsupported operation');
-  }
-
-  /** @abstract */
-  getParent() {
-    throw new Error('Unsupported operation');
-  }
-
-  /** @abstract */
-  clone() {
-    throw new Error('Unsupported operation');
-  }
-
-  /** */
   inspect() {
     let result = `{ type: ${this.getType()} , id: ${this.getId()} , text: ${this.getText()}`;
 
@@ -369,16 +391,14 @@ class INodeModel {
     return result;
   }
 
-  /** @abstract */
-  // eslint-disable-next-line no-unused-vars
-  removeChild(child) {
-    throw new Error('Unsupported operation');
-  }
+  abstract removeChild(child: INodeModel);
+
+  static _nextUUID(): number {
+    INodeModel._next_uuid += 1;
+    return INodeModel._next_uuid;
+  };
 }
 
-/**
- * @enum {String}
- */
 const TopicShape = {
   RECTANGLE: 'rectagle',
   ROUNDED_RECT: 'rounded rectagle',
@@ -387,38 +407,10 @@ const TopicShape = {
   IMAGE: 'image',
 };
 
-/**
- * @constant
- * @type {String}
- * @default
- */
-INodeModel.CENTRAL_TOPIC_TYPE = 'CentralTopic';
-/**
- * @constant
- * @type {String}
- * @default
- */
-INodeModel.MAIN_TOPIC_TYPE = 'MainTopic';
-
-/**
- * @constant
- * @type {Number}
- * @default
- */
-INodeModel.MAIN_TOPIC_TO_MAIN_TOPIC_DISTANCE = 220;
+export type NodeModelType = 'CentralTopic' | 'MainTopic';
 
 /**
  * @todo: This method must be implemented. (unascribed)
  */
-INodeModel._nextUUID = () => {
-  if (!$defined(INodeModel._uuid)) {
-    INodeModel._uuid = 0;
-  }
-
-  INodeModel._uuid += 1;
-  return INodeModel._uuid;
-};
-INodeModel._uuid = 0;
-
 export { TopicShape };
 export default INodeModel;
diff --git a/packages/mindplot/src/components/model/IconModel.js b/packages/mindplot/src/components/model/IconModel.ts
similarity index 81%
rename from packages/mindplot/src/components/model/IconModel.js
rename to packages/mindplot/src/components/model/IconModel.ts
index ef3279ae..b605db74 100644
--- a/packages/mindplot/src/components/model/IconModel.js
+++ b/packages/mindplot/src/components/model/IconModel.ts
@@ -20,27 +20,17 @@ import FeatureModel from './FeatureModel';
 
 class IconModel extends FeatureModel {
   constructor(attributes) {
-    super(IconModel.FEATURE_TYPE);
+    super('icon');
     this.setIconType(attributes.id);
   }
 
-  /** @return the icon type id */
-  getIconType() {
+  getIconType(): string {
     return this.getAttribute('id');
   }
 
-  /** @param {String} iconType the icon type id */
-  setIconType(iconType) {
+  setIconType(iconType: string) {
     $assert(iconType, 'iconType id can not be null');
     this.setAttribute('id', iconType);
   }
 }
-
-/**
- * @constant
- * @type {String}
- * @default
- */
-IconModel.FEATURE_TYPE = 'icon';
-
 export default IconModel;
diff --git a/packages/mindplot/src/components/model/LinkModel.js b/packages/mindplot/src/components/model/LinkModel.ts
similarity index 92%
rename from packages/mindplot/src/components/model/LinkModel.js
rename to packages/mindplot/src/components/model/LinkModel.ts
index ed23b609..7cb9fad0 100644
--- a/packages/mindplot/src/components/model/LinkModel.js
+++ b/packages/mindplot/src/components/model/LinkModel.ts
@@ -20,7 +20,7 @@ import FeatureModel from './FeatureModel';
 
 class LinkModel extends FeatureModel {
   constructor(attributes) {
-    super(LinkModel.FEATURE_TYPE);
+    super('link');
     this.setUrl(attributes.url);
   }
 
@@ -33,7 +33,7 @@ class LinkModel extends FeatureModel {
      * @param {String} url a URL provided by the user to set the link to
      * @throws will throw an error if url is null or undefined
      */
-  setUrl(url) {
+  setUrl(url: string): void {
     $assert(url, 'url can not be null');
 
     const fixedUrl = LinkModel._fixUrl(url);
@@ -44,7 +44,7 @@ class LinkModel extends FeatureModel {
   }
 
   // url format is already checked in LinkEditor.checkUrl
-  static _fixUrl(url) {
+  static _fixUrl(url: string): string {
     let result = url;
     if (!result.includes('http://') && !result.includes('https://') && !result.includes('mailto://')) {
       result = `http://${result}`;
@@ -61,12 +61,4 @@ class LinkModel extends FeatureModel {
     this.setAttribute('urlType', urlType);
   }
 }
-
-/**
- * @constant
- * @type {String}
- * @default
- */
-LinkModel.FEATURE_TYPE = 'link';
-
 export default LinkModel;
diff --git a/packages/mindplot/src/components/model/Mindmap.ts b/packages/mindplot/src/components/model/Mindmap.ts
index e1be88b9..b8e58336 100644
--- a/packages/mindplot/src/components/model/Mindmap.ts
+++ b/packages/mindplot/src/components/model/Mindmap.ts
@@ -17,7 +17,7 @@
  */
 import { $assert, $defined } from '@wisemapping/core-js';
 import IMindmap from './IMindmap';
-import INodeModel from './INodeModel';
+import INodeModel, { NodeModelType } from './INodeModel';
 import NodeModel from './NodeModel';
 import RelationshipModel from './RelationshipModel';
 import ModelCodeName from '../persistence/ModelCodeName';
@@ -79,10 +79,10 @@ class Mindmap extends IMindmap {
     $assert(nodeModel && nodeModel.isNodeModel(), 'Add node must be invoked with model objects');
     const branches = this.getBranches();
     if (branches.length === 0) {
-      $assert(nodeModel.getType() === INodeModel.CENTRAL_TOPIC_TYPE, 'First element must be the central topic');
+      $assert(nodeModel.getType() === 'CentralTopic', 'First element must be the central topic');
       nodeModel.setPosition(0, 0);
     } else {
-      $assert(nodeModel.getType() !== INodeModel.CENTRAL_TOPIC_TYPE, 'Mindmaps only have one cental topic');
+      $assert(nodeModel.getType() !== 'CentralTopic', 'Mindmaps only have one cental topic');
     }
 
     this._branches.push(nodeModel);
@@ -91,7 +91,7 @@ class Mindmap extends IMindmap {
   /**
          * @param nodeModel
          */
-  removeBranch(nodeModel: NodeModel): void {
+  removeBranch(nodeModel: INodeModel): void {
     $assert(nodeModel && nodeModel.isNodeModel(), 'Remove node must be invoked with model objects');
     this._branches = this._branches.filter((b) => b !== nodeModel);
   }
@@ -104,29 +104,22 @@ class Mindmap extends IMindmap {
     return this._relationships;
   }
 
-  /**
-         * @param node
-         * @return {Boolean} true if node already exists
-         */
-  hasAlreadyAdded(node: any) {
+
+  hasAlreadyAdded(node: NodeModel): boolean {
     let result = false;
 
     // Check in not connected nodes.
     const branches = this._branches;
     for (let i = 0; i < branches.length; i++) {
-      result = branches[i]._isChildNode(node);
+      result = branches[i].isChildNode(node);
       if (result) {
         break;
       }
     }
+    return result;
   }
 
-  /**
-         * @param type
-         * @param id
-         * @return the node model created
-         */
-  createNode(type = INodeModel.MAIN_TOPIC_TYPE, id: number) {
+  createNode(type: NodeModelType = 'MainTopic', id: number) {
     return new NodeModel(type, this, id);
   }
 
@@ -172,7 +165,7 @@ class Mindmap extends IMindmap {
 
   static buildEmpty = (mapId: string) => {
     const result = new Mindmap(mapId);
-    const node = result.createNode(INodeModel.CENTRAL_TOPIC_TYPE, 0);
+    const node = result.createNode('CentralTopic', 0);
     result.addBranch(node);
     return result;
   };
diff --git a/packages/mindplot/src/components/model/NodeModel.js b/packages/mindplot/src/components/model/NodeModel.ts
similarity index 71%
rename from packages/mindplot/src/components/model/NodeModel.js
rename to packages/mindplot/src/components/model/NodeModel.ts
index af440777..39c9c177 100644
--- a/packages/mindplot/src/components/model/NodeModel.js
+++ b/packages/mindplot/src/components/model/NodeModel.ts
@@ -17,21 +17,28 @@
  */
 import { $assert, $defined } from '@wisemapping/core-js';
 import cloneDeep from 'lodash/cloneDeep';
-import INodeModel from './INodeModel';
+import INodeModel, { NodeModelType } from './INodeModel';
 import FeatureModelFactory from './FeatureModelFactory';
+import FeatureModel from './FeatureModel';
+import Mindmap from './Mindmap';
 
 class NodeModel extends INodeModel {
-  constructor(type, mindmap, id) {
+  _properties: {};
+  _children: INodeModel[];
+  _features: FeatureModel[];
+  _parent: INodeModel;
+
+  constructor(type: NodeModelType, mindmap: Mindmap, id: number) {
     $assert(type, 'Node type can not be null');
     $assert(mindmap, 'mindmap can not be null');
     super(mindmap);
     this._properties = {};
     this.setId(id);
     this.setType(type);
-    this.areChildrenShrunken(false);
+    this.areChildrenShrunken();
 
     this._children = [];
-    this._feature = [];
+    this._features = [];
   }
 
   /**
@@ -49,12 +56,12 @@ class NodeModel extends INodeModel {
      */
   addFeature(feature) {
     $assert(feature, 'feature can not be null');
-    this._feature.push(feature);
+    this._features.push(feature);
   }
 
   /** */
   getFeatures() {
-    return this._feature;
+    return this._features;
   }
 
   /**
@@ -64,9 +71,9 @@ class NodeModel extends INodeModel {
      */
   removeFeature(feature) {
     $assert(feature, 'feature can not be null');
-    const size = this._feature.length;
-    this._feature = this._feature.filter((f) => feature.getId() !== f.getId());
-    $assert(size - 1 === this._feature.length, 'Could not be removed ...');
+    const size = this._features.length;
+    this._features = this._features.filter((f) => feature.getId() !== f.getId());
+    $assert(size - 1 === this._features.length, 'Could not be removed ...');
   }
 
   /**
@@ -75,7 +82,7 @@ class NodeModel extends INodeModel {
      */
   findFeatureByType(type) {
     $assert(type, 'type can not be null');
-    return this._feature.filter((feature) => feature.getType() === type);
+    return this._features.filter((feature) => feature.getType() === type);
   }
 
   /**
@@ -86,7 +93,7 @@ class NodeModel extends INodeModel {
      */
   findFeatureById(id) {
     $assert($defined(id), 'id can not be null');
-    const result = this._feature.filter((feature) => feature.getId() === id);
+    const result = this._features.filter((feature) => feature.getId() === id);
     $assert(result.length === 1, `Feature could not be found:${id}`);
     return result[0];
   }
@@ -112,7 +119,7 @@ class NodeModel extends INodeModel {
   }
 
   /** */
-  getProperty(key) {
+  getProperty(key: string) {
     $defined(key, 'key can not be null');
     const result = this._properties[key];
     return !$defined(result) ? null : result;
@@ -122,15 +129,15 @@ class NodeModel extends INodeModel {
      * @return {mindplot.model.NodeModel} an identical clone of the NodeModel
      */
   clone() {
-    const result = new NodeModel(this.getType(), this._mindmap);
+    const result = new NodeModel(this.getType(), this._mindmap, -1);
     result._children = this._children.map((node) => {
-      const cnode = node.clone();
+      const cnode = node.clone() as NodeModel;
       cnode._parent = result;
       return cnode;
     });
 
     result._properties = cloneDeep(this._properties);
-    result._feature = cloneDeep(this._feature);
+    result._features = cloneDeep(this._features);
     return result;
   }
 
@@ -138,19 +145,19 @@ class NodeModel extends INodeModel {
      * Similar to clone, assign new id to the elements ...
      * @return {mindplot.model.NodeModel}
      */
-  deepCopy() {
-    const result = new NodeModel(this.getType(), this._mindmap);
+  deepCopy(): NodeModel {
+    const result = new NodeModel(this.getType(), this._mindmap, -1);
     result._children = this._children.map((node) => {
-      const cnode = node.deepCopy();
+      const cnode = (node as NodeModel).deepCopy();
       cnode._parent = result;
       return cnode;
     });
 
     const id = result.getId();
-    result._properties = Object.clone(this._properties);
+    result._properties = Object.assign({}, this._properties);
     result.setId(id);
 
-    result._feature = this._feature.clone();
+    result._features = cloneDeep(this._features);
     return result;
   }
 
@@ -158,7 +165,7 @@ class NodeModel extends INodeModel {
      * @param {mindplot.model.NodeModel} child
      * @throws will throw an error if child is null, undefined or not a NodeModel object
      */
-  append(child) {
+  append(child: NodeModel) {
     $assert(child && child.isNodeModel(), 'Only NodeModel can be appended to Mindmap object');
     this._children.push(child);
     // eslint-disable-next-line no-param-reassign
@@ -169,7 +176,7 @@ class NodeModel extends INodeModel {
      * @param {mindplot.model.NodeModel} child
      * @throws will throw an error if child is null, undefined or not a NodeModel object
      */
-  removeChild(child) {
+  removeChild(child): void {
     $assert(child && child.isNodeModel(), 'Only NodeModel can be appended to Mindmap object.');
     this._children = this._children.filter((c) => c !== child);
     // eslint-disable-next-line no-param-reassign
@@ -192,44 +199,6 @@ class NodeModel extends INodeModel {
     this._parent = parent;
   }
 
-  _isChildNode(node) {
-    let result = false;
-    if (node === this) {
-      result = true;
-    } else {
-      const children = this.getChildren();
-      for (let i = 0; i < children.length; i++) {
-        const child = children[i];
-        result = child._isChildNode(node);
-        if (result) {
-          break;
-        }
-      }
-    }
-    return result;
-  }
-
-  /**
-     * @id
-     * @return {mindplot.model.NodeModel} the node with the respective id
-     */
-  findNodeById(id) {
-    $assert(Number.isFinite(id));
-    let result = null;
-    if (this.getId() === id) {
-      result = this;
-    } else {
-      const children = this.getChildren();
-      for (let i = 0; i < children.length; i++) {
-        const child = children[i];
-        result = child.findNodeById(id);
-        if (result) {
-          break;
-        }
-      }
-    }
-    return result;
-  }
 }
 
 export default NodeModel;
diff --git a/packages/mindplot/src/components/model/NoteModel.js b/packages/mindplot/src/components/model/NoteModel.ts
similarity index 91%
rename from packages/mindplot/src/components/model/NoteModel.js
rename to packages/mindplot/src/components/model/NoteModel.ts
index bb344c48..8d289931 100644
--- a/packages/mindplot/src/components/model/NoteModel.js
+++ b/packages/mindplot/src/components/model/NoteModel.ts
@@ -20,7 +20,7 @@ import FeatureModel from './FeatureModel';
 
 class NoteModel extends FeatureModel {
   constructor(attributes) {
-    super(NoteModel.FEATURE_TYPE);
+    super('note');
     const noteText = attributes.text ? attributes.text : ' ';
     this.setText(noteText);
   }
@@ -37,11 +37,4 @@ class NoteModel extends FeatureModel {
   }
 }
 
-/**
- * @constant
- * @type {String}
- * @default
- */
-NoteModel.FEATURE_TYPE = 'note';
-
 export default NoteModel;
diff --git a/packages/mindplot/src/components/model/RelationshipModel.js b/packages/mindplot/src/components/model/RelationshipModel.ts
similarity index 86%
rename from packages/mindplot/src/components/model/RelationshipModel.js
rename to packages/mindplot/src/components/model/RelationshipModel.ts
index b7f4432c..cea0f996 100644
--- a/packages/mindplot/src/components/model/RelationshipModel.js
+++ b/packages/mindplot/src/components/model/RelationshipModel.ts
@@ -19,7 +19,17 @@ import { $assert, $defined } from '@wisemapping/core-js';
 import ConnectionLine from '../ConnectionLine';
 
 class RelationshipModel {
-  constructor(sourceTopicId, targetTopicId) {
+  static _next_uuid: number = 0;
+  _id: number;
+  _sourceTargetId: number;
+  _targetTopicId: number;
+  _lineType: number;
+  _srcCtrlPoint: any;
+  _destCtrlPoint: any;
+  _endArrow: boolean;
+  _startArrow: boolean;
+
+  constructor(sourceTopicId: number, targetTopicId: number) {
     $assert($defined(sourceTopicId), 'from node type can not be null');
     $assert($defined(targetTopicId), 'to node type can not be null');
     $assert(Number.isFinite(sourceTopicId), 'sourceTopicId is not a number');
@@ -118,23 +128,19 @@ class RelationshipModel {
   /**
        * @return {String} textual information about the relationship's source and target node
        */
-  inspect() {
+  inspect(): string {
     return (
-      `(fromNode:${this.getFromNode().getId()
-      } , toNode: ${this.getToNode().getId()
+      `(fromNode:${this.getFromNode()
+      } , toNode: ${this.getToNode()
       })`
     );
   }
-}
 
-function _nextUUID() {
-  if (!$defined(RelationshipModel._uuid)) {
-    RelationshipModel._uuid = 0;
+  static _nextUUID() {
+    RelationshipModel._next_uuid += 1;
+    return RelationshipModel._next_uuid;
   }
-  RelationshipModel._uuid += 1;
-  return RelationshipModel._uuid;
 }
 
-RelationshipModel._nextUUID = _nextUUID;
 
 export default RelationshipModel;