diff --git a/.babelrc b/.babelrc
index c13c5f6..e81a8fb 100755
--- a/.babelrc
+++ b/.babelrc
@@ -1,3 +1,3 @@
 {
-  "presets": ["es2015"]
+  "presets": ["es2015", "stage-3", "stage-2"]
 }
diff --git a/gulpfile.js b/gulpfile.js
index 85cc649..1aec6d0 100644
--- a/gulpfile.js
+++ b/gulpfile.js
@@ -4,6 +4,7 @@ var gutil = require('gulp-util');
 var shell = require('gulp-shell');
 var mkdirp = require('mkdirp');
 var webpack = require('webpack');
+var WebpackDevServer = require('webpack-dev-server');
 
 var NAME    = 'jsoneditor';
 var NAME_MINIMALIST = 'jsoneditor-minimalist';
@@ -37,6 +38,7 @@ var loaders = [
 var compiler = webpack({
   entry: ENTRY,
   devtool: 'source-map',
+  debug: true,
   output: {
     library: 'jsoneditor',
     libraryTarget: 'umd',
@@ -57,6 +59,7 @@ var compiler = webpack({
 var compilerMinimalist = webpack({
   entry: ENTRY,
   devtool: 'source-map',
+  debug: true,
   output: {
     library: 'jsoneditor',
     libraryTarget: 'umd',
@@ -87,7 +90,7 @@ gulp.task('bundle', ['mkdir'], function (done) {
 
   compiler.run(function (err, stats) {
     if (err) {
-      gutil.log(err);
+      throw new gutil.PluginError('webpack', err);
     }
 
     gutil.log('bundled ' + NAME + '.js');
@@ -103,7 +106,7 @@ gulp.task('bundle-minimalist', ['mkdir'], function (done) {
 
   compilerMinimalist.run(function (err, stats) {
     if (err) {
-      gutil.log(err);
+      throw new gutil.PluginError('webpack', err);
     }
 
     gutil.log('bundled ' + NAME_MINIMALIST + '.js');
diff --git a/package.json b/package.json
index d920c0b..dd074b2 100644
--- a/package.json
+++ b/package.json
@@ -23,15 +23,17 @@
     "test": "ava test/*.test.js test/**/*.test.js --verbose"
   },
   "dependencies": {
-    "ajv": "4.4.0",
+    "ajv": "4.5.0",
     "brace": "0.8.0",
     "javascript-natural-sort": "0.7.1",
-    "preact": "5.6.0"
+    "preact": "5.7.0"
   },
   "devDependencies": {
     "ava": "0.16.0",
     "babel-core": "6.13.2",
-    "babel-loader": "6.2.4",
+    "babel-loader": "6.2.5",
+    "babel-preset-stage-2": "6.13.0",
+    "babel-preset-stage-3": "6.11.0",
     "css-loader": "0.23.1",
     "gulp": "3.9.1",
     "gulp-shell": "0.5.2",
@@ -42,7 +44,7 @@
     "mkdirp": "0.5.1",
     "style-loader": "0.13.1",
     "svg-url-loader": "1.1.0",
-    "webpack": "1.13.1"
+    "webpack": "1.13.2"
   },
   "ava": {
     "require": [
diff --git a/src/TreeMode.js b/src/TreeMode.js
index 5f31ae6..989499e 100644
--- a/src/TreeMode.js
+++ b/src/TreeMode.js
@@ -1,11 +1,13 @@
 import { h, Component } from 'preact'
 
-import { cloneDeep } from './utils/objectUtils'
-import { setIn, updateIn, getIn, deleteIn } from './utils/immutabilityHelpers'
-import { compareAsc, compareDesc } from './utils/arrayUtils'
-import { stringConvert } from  './utils/typeUtils'
-import { isObject } from './utils/objectUtils'
-import bindMethods from './utils/bindMethods'
+import { setIn } from './utils/immutabilityHelpers'
+import {
+  changeValue, changeProperty, changeType,
+  insert, append, duplicate, remove,
+  sort,
+  expand,
+  jsonToData, dataToJson
+} from './jsonData'
 import JSONNode from './JSONNode'
 
 export default class TreeMode extends Component {
@@ -14,11 +16,9 @@ export default class TreeMode extends Component {
   constructor (props) {
     super(props)
 
-    bindMethods(this)
-
     const name   = this.props.options && this.props.options.name || null
     const expand = this.props.options && this.props.options.expand || TreeMode.expand
-    
+
     this.state = {
       options: {
         name
@@ -43,13 +43,13 @@ export default class TreeMode extends Component {
     }
   }
 
-  render() {
+  render (props, state) {
     return h('div', {class: 'jsoneditor', contentEditable: 'false', onClick: JSONNode.hideContextMenu}, [
       h('ul', {class: 'jsoneditor-list', contentEditable: 'false'}, [
         h(JSONNode, {
-          data: this.state.data,
-          events: this.state.events,
-          options: this.state.options,
+          data: state.data,
+          events: state.events,
+          options: state.options,
           parent: null,
           prop: null
         })
@@ -57,224 +57,57 @@ export default class TreeMode extends Component {
     ])
   }
 
-  handleChangeValue (path, value) {
-    console.log('handleChangeValue', path, value)
-
-    const dataPath = toDataPath(this.state.data, path)
-
+  handleChangeValue = (path, value) => {
     this.setState({
-      data: setIn(this.state.data, dataPath.concat(['value']), value)
+      data: changeValue(this.state.data, path, value)
     })
   }
 
-  handleChangeProperty (path, oldProp, newProp) {
-    console.log('handleChangeProperty', path, oldProp, newProp)
-
-    const dataPath = toDataPath(this.state.data, path)
-    const object = getIn(this.state.data, dataPath)
-    const index = object.props.findIndex(p => p.name === oldProp)
-
+  handleChangeProperty = (path, oldProp, newProp) => {
     this.setState({
-      data: setIn(this.state.data, dataPath.concat(['props', index, 'name']), newProp)
+      data: changeProperty(this.state.data, path, oldProp, newProp)
     })
   }
 
-  handleChangeType (path, type) {
-    console.log('handleChangeType', path, type)
-
-    const dataPath = toDataPath(this.state.data, path)
-    const oldEntry = getIn(this.state.data, dataPath)
-    const newEntry = convertDataEntry(oldEntry, type)
-
+  handleChangeType = (path, type) => {
     this.setState({
-      data: setIn(this.state.data, dataPath, newEntry)
+      data: changeType(this.state.data, path, type)
     })
   }
 
-  handleInsert (path, afterProp, type) {
-    console.log('handleInsert', path, afterProp, type)
-
-    const dataPath = toDataPath(this.state.data, path)
-    const parent = getIn(this.state.data, dataPath)
-
-    if (parent.type === 'array') {
-      this.setState({
-        data: updateIn(this.state.data, dataPath.concat(['items']), (items) => {
-          const index = parseInt(afterProp)
-          const updatedItems = items.slice(0)
-
-          updatedItems.splice(index + 1, 0, createDataEntry(type))
-
-          return updatedItems
-        })
-      })
-    }
-    else { // parent.type === 'object'
-      this.setState({
-        data: updateIn(this.state.data, dataPath.concat(['props']), (props) => {
-          const index = props.findIndex(p => p.name === afterProp)
-          const updatedProps = props.slice(0)
-
-          updatedProps.splice(index + 1, 0, {
-            name: '',
-            value: createDataEntry(type)
-          })
-
-          return updatedProps
-        })
-      })
-    }
-  }
-
-  handleAppend (path, type) {
-    console.log('handleAppend', path, type)
-
-    const dataPath = toDataPath(this.state.data, path)
-    const object = getIn(this.state.data, dataPath)
-
-    if (object.type === 'array') {
-      this.setState({
-        data: updateIn(this.state.data, dataPath.concat(['items']), (items) => {
-          const updatedItems = items.slice(0)
-
-          updatedItems.push(createDataEntry(type))
-
-          return updatedItems
-        })
-      })
-    }
-    else { // object.type === 'object'
-      this.setState({
-        data: updateIn(this.state.data, dataPath.concat(['props']), (props) => {
-          const updatedProps = props.slice(0)
-
-          updatedProps.push({
-            name: '',
-            value: createDataEntry(type)
-          })
-
-          return updatedProps
-        })
-      })
-    }
-  }
-
-  handleDuplicate (path, prop) {
-    console.log('handleDuplicate', path)
-
-    const dataPath = toDataPath(this.state.data, path)
-    const object = getIn(this.state.data, dataPath)
-
-    if (object.type === 'array') {
-      this.setState({
-        data: updateIn(this.state.data, dataPath.concat(['items']), (items) => {
-          const index = parseInt(prop)
-          const updatedItems = items.slice(0)
-          const original = items[index]
-          const duplicate = cloneDeep(original)
-
-          updatedItems.splice(index + 1, 0, duplicate)
-
-          return updatedItems
-        })
-      })
-    }
-    else { // object.type === 'object'
-      this.setState({
-        data: updateIn(this.state.data, dataPath.concat(['props']), (props) => {
-          const index = props.findIndex(p => p.name === prop)
-          const updated = props.slice(0)
-          const original = props[index]
-          const duplicate = cloneDeep(original)
-
-          updated.splice(index + 1, 0, duplicate)
-
-          return updated
-        })
-      })
-    }
-  }
-
-  handleRemove (path, prop) {
-    console.log('handleRemove', path)
-
-    const object = getIn(this.state.data, toDataPath(this.state.data, path))
-
-    if (object.type === 'array') {
-      const dataPath = toDataPath(this.state.data, path.concat(prop))
-
-      this.setState({
-        data: deleteIn(this.state.data, dataPath)
-      })
-    }
-    else { // object.type === 'object'
-      const dataPath = toDataPath(this.state.data, path.concat(prop))
-
-      dataPath.pop()  // remove the 'value' property, we want to remove the whole object property
-      this.setState({
-        data: deleteIn(this.state.data, dataPath)
-      })
-    }
-  }
-
-  /**
-   * Order the items of an array or the properties of an object in ascending
-   * or descending order
-   * @param {Array.<string | number>} path
-   * @param {'asc' | 'desc' | null} [order=null]  If not provided, will toggle current ordering
-   */
-  handleSort (path, order = null) {
-    console.log('handleSort', path, order)
-
-    const dataPath = toDataPath(this.state.data, path)
-    const object = getIn(this.state.data, dataPath)
-
-    let _order
-    if (order === 'asc' || order === 'desc') {
-      _order = order
-    }
-    else {
-      // toggle previous order
-      _order = object.order !== 'asc' ? 'asc' : 'desc'
-
-      this.setState({
-        data: setIn(this.state.data, dataPath.concat(['order']), _order)
-      })
-    }
-
-    if (object.type === 'array') {
-      this.setState({
-        data: updateIn(this.state.data, dataPath.concat(['items']), (items) =>{
-          const ordered = items.slice(0)
-          const compare = _order === 'desc' ? compareDesc : compareAsc
-
-          ordered.sort((a, b) => compare(a.value, b.value))
-
-          return ordered
-        })
-      })
-    }
-    else { // object.type === 'object'
-      this.setState({
-        data: updateIn(this.state.data, dataPath.concat(['props']), (props) => {
-          const orderedProps = props.slice(0)
-          const compare = _order === 'desc' ? compareDesc : compareAsc
-
-          orderedProps.sort((a, b) => compare(a.name, b.name))
-
-          return orderedProps
-        })
-      })
-    }
-  }
-
-  handleExpand(path, expand) {
-    console.log('handleExpand', path, expand)
-
-    const dataPath = toDataPath(this.state.data, path)
-
+  handleInsert = (path, afterProp, type) => {
     this.setState({
-      data: setIn(this.state.data, dataPath.concat(['expanded']), expand)
+      data: insert(this.state.data, path, afterProp, type)
+    })
+  }
+
+  handleAppend = (path, type) => {
+    this.setState({
+      data: append(this.state.data, path, type)
+    })
+  }
+
+  handleDuplicate = (path, type) => {
+    this.setState({
+      data: duplicate(this.state.data, path, type)
+    })
+  }
+
+  handleRemove = (path, prop) => {
+    this.setState({
+      data: remove(this.state.data, path, prop)
+    })
+  }
+
+  handleSort = (path, order = null) => {
+    this.setState({
+      data: sort(this.state.data, path, order)
+    })
+  }
+
+  handleExpand = (path, doExpand) => {
+    this.setState({
+      data: expand(this.state.data, path, doExpand)
     })
   }
 
@@ -315,151 +148,3 @@ export default class TreeMode extends Component {
   }
 
 }
-
-/**
- * Convert a path of a JSON object into a path in the corresponding data model
- * @param {Data} data
- * @param {Array.<string | number>} path
- * @return {Array.<string | number>} dataPath
- * @private
- */
-function toDataPath (data, path) {
-  if (path.length === 0) {
-    return []
-  }
-
-  let index
-  if (data.type === 'array') {
-    // index of an array
-    index = path[0]
-
-    return ['items', index].concat(toDataPath(data.items[index], path.slice(1)))
-  }
-  else {
-    // object property. find the index of this property
-    index = data.props.findIndex(prop => prop.name === path[0])
-
-    return ['props', index, 'value'].concat(toDataPath(data.props[index].value, path.slice(1)))
-  }
-}
-
-/**
- * Convert a JSON object into the internally used data model
- * @param {Array.<string | number>} path
- * @param {Object | Array | string | number | boolean | null} json
- * @param {function(path: Array.<string | number>)} expand
- * @return {Data}
- */
-function jsonToData (path, json, expand) {
-  if (Array.isArray(json)) {
-    return {
-      type: 'array',
-      expanded: expand(path),
-      items: json.map((child, index) => jsonToData(path.concat(index), child, expand))
-    }
-  }
-  else if (isObject(json)) {
-    return {
-      type: 'object',
-      expanded: expand(path),
-      props: Object.keys(json).map(name => {
-        return {
-          name,
-          value: jsonToData(path.concat(name), json[name], expand)
-        }
-      })
-    }
-  }
-  else {
-    return {
-      type: 'value',
-      value: json
-    }
-  }
-}
-
-/**
- * Convert the internal data model to a regular JSON object
- * @param {Data} data
- * @return {Object | Array | string | number | boolean | null} json
- */
-function dataToJson (data) {
-  switch (data.type) {
-    case 'array':
-      return data.items.map(dataToJson)
-
-    case 'object':
-      const object = {}
-
-      data.props.forEach(prop => {
-        object[prop.name] = dataToJson(prop.value)
-      })
-
-      return object
-
-    default: // type 'string' or 'value'
-      return data.value
-  }
-}
-
-
-/**
- * Create a new data entry
- * @param {'object' | 'array' | 'value' | 'string'} [type='value']
- * @return {*}
- */
-function createDataEntry (type) {
-  if (type === 'array') {
-    return {
-      type,
-      expanded: true,
-      items: []
-    }
-  }
-  else if (type === 'object') {
-    return {
-      type,
-      expanded: true,
-      props: []
-    }
-  }
-  else {
-    return {
-      type,
-      value: ''
-    }
-  }
-}
-
-/**
- * Convert an entry into a different type. When possible, data is retained
- * @param {Data} entry
- * @param {'object' | 'array' | 'value' | 'string'} type
- */
-function convertDataEntry (entry, type) {
-  const convertedEntry = createDataEntry(type)
-
-  // convert contents from old value to new value where possible
-  if (type === 'value' && entry.type === 'string') {
-    convertedEntry.value = stringConvert(entry.value)
-  }
-
-  if (type === 'string' && entry.type === 'value') {
-    convertedEntry.value = entry.value + ''
-  }
-
-  if (type === 'object' && entry.type === 'array') {
-    convertedEntry.props = entry.items.map((item, index) => {
-      return {
-        name: index + '',
-        value: item
-      }
-    })
-  }
-
-  if (type === 'array' && entry.type === 'object') {
-    convertedEntry.items = entry.props.map(prop => prop.value)
-  }
-
-  return convertedEntry
-}
\ No newline at end of file
diff --git a/src/jsonData.js b/src/jsonData.js
new file mode 100644
index 0000000..1c5c64c
--- /dev/null
+++ b/src/jsonData.js
@@ -0,0 +1,410 @@
+/**
+ * This file contains functions to act on a JSONData object.
+ * All functions are pure and don't mutate the JSONData.
+ */
+
+import { cloneDeep } from './utils/objectUtils'
+import { setIn, updateIn, getIn, deleteIn } from './utils/immutabilityHelpers'
+import { compareAsc, compareDesc } from './utils/arrayUtils'
+import { stringConvert } from  './utils/typeUtils'
+import { isObject } from './utils/objectUtils'
+
+/**
+ * Change the value of a property or item
+ * @param {JSONData} data
+ * @param {Path} path
+ * @param {*} value
+ * @return {JSONData}
+ */
+export function changeValue (data, path, value) {
+  console.log('changeValue', data, value)
+
+  const dataPath = toDataPath(data, path)
+
+  return setIn(data, dataPath.concat(['value']), value)
+}
+
+/**
+ * Change a property name
+ * @param {JSONData} data
+ * @param {Path} path
+ * @param {string} oldProp
+ * @param {string} newProp
+ * @return {JSONData}
+ */
+export function changeProperty (data, path, oldProp, newProp) {
+  console.log('changeProperty', path, oldProp, newProp)
+
+  const dataPath = toDataPath(data, path)
+  const object = getIn(data, dataPath)
+  const index = object.props.findIndex(p => p.name === oldProp)
+
+  return setIn(data, dataPath.concat(['props', index, 'name']), newProp)
+}
+
+/**
+ * Change the type of a property or item
+ * @param {JSONData} data
+ * @param {Path} path
+ * @param {JSONDataType} type
+ * @return {JSONData}
+ */
+export function changeType (data, path, type) {
+  console.log('changeType', path, type)
+
+  const dataPath = toDataPath(data, path)
+  const oldEntry = getIn(data, dataPath)
+  const newEntry = convertDataEntry(oldEntry, type)
+
+  return setIn(data, dataPath, newEntry)
+}
+
+/**
+ * Insert a new item after specified property or item
+ * @param {JSONData} data
+ * @param {Path} path
+ * @param {string | number} afterProp
+ * @param {JSONDataType} type
+ * @return {JSONData}
+ */
+export function insert (data, path, afterProp, type) {
+  console.log('insert', path, afterProp, type)
+
+  const dataPath = toDataPath(data, path)
+  const parent = getIn(data, dataPath)
+
+  if (parent.type === 'array') {
+    return updateIn(data, dataPath.concat(['items']), (items) => {
+      const index = parseInt(afterProp)
+      const updatedItems = items.slice(0)
+
+      updatedItems.splice(index + 1, 0, createDataEntry(type))
+
+      return updatedItems
+    })
+  }
+  else { // parent.type === 'object'
+    return updateIn(data, dataPath.concat(['props']), (props) => {
+      const index = props.findIndex(p => p.name === afterProp)
+      const updatedProps = props.slice(0)
+
+      updatedProps.splice(index + 1, 0, {
+        name: '',
+        value: createDataEntry(type)
+      })
+
+      return updatedProps
+    })
+  }
+}
+
+/**
+ * Append a new item at the end of an object or array
+ * @param {JSONData} data
+ * @param {Path} path
+ * @param {JSONDataType} type
+ * @return {JSONData}
+ */
+export function append (data, path, type) {
+  console.log('append', path, type)
+
+  const dataPath = toDataPath(data, path)
+  const object = getIn(data, dataPath)
+
+  if (object.type === 'array') {
+    return updateIn(data, dataPath.concat(['items']), (items) => {
+      const updatedItems = items.slice(0)
+
+      updatedItems.push(createDataEntry(type))
+
+      return updatedItems
+    })
+  }
+  else { // object.type === 'object'
+    return updateIn(data, dataPath.concat(['props']), (props) => {
+      const updatedProps = props.slice(0)
+
+      updatedProps.push({
+        name: '',
+        value: createDataEntry(type)
+      })
+
+      return updatedProps
+    })
+  }
+}
+
+/**
+ * Duplicate a property or item
+ * @param {JSONData} data
+ * @param {Path} path
+ * @param {string | number} prop
+ * @return {JSONData}
+ */
+export function duplicate (data, path, prop) {
+  console.log('duplicate', path)
+
+  const dataPath = toDataPath(data, path)
+  const object = getIn(data, dataPath)
+
+  if (object.type === 'array') {
+    return updateIn(data, dataPath.concat(['items']), (items) => {
+      const index = parseInt(prop)
+      const updatedItems = items.slice(0)
+      const original = items[index]
+      const duplicate = cloneDeep(original)
+
+      updatedItems.splice(index + 1, 0, duplicate)
+
+      return updatedItems
+    })
+  }
+  else { // object.type === 'object'
+    return updateIn(data, dataPath.concat(['props']), (props) => {
+      const index = props.findIndex(p => p.name === prop)
+      const updated = props.slice(0)
+      const original = props[index]
+      const duplicate = cloneDeep(original)
+
+      updated.splice(index + 1, 0, duplicate)
+
+      return updated
+    })
+  }
+}
+
+/**
+ * Remove an item or property
+ * @param {JSONData} data
+ * @param {Path} path
+ * @param {string | number} prop
+ * @return {JSONData}
+ */
+export function remove (data, path, prop) {
+  console.log('remove', path)
+
+  const object = getIn(data, toDataPath(data, path))
+
+  if (object.type === 'array') {
+    const dataPath = toDataPath(data, path.concat(prop))
+
+    return deleteIn(data, dataPath)
+  }
+  else { // object.type === 'object'
+    const dataPath = toDataPath(data, path.concat(prop))
+
+    dataPath.pop()  // remove the 'value' property, we want to remove the whole object property
+    return deleteIn(data, dataPath)
+  }
+}
+
+/**
+ * Order the items of an array or the properties of an object in ascending
+ * or descending order
+ * @param {JSONData} data
+ * @param {Path} path
+ * @param {'asc' | 'desc' | null} [order=null]  If not provided, will toggle current ordering
+ * @return {JSONData}
+ */
+export function sort (data, path, order = null) {
+  console.log('sort', path, order)
+
+  const dataPath = toDataPath(data, path)
+  const object = getIn(data, dataPath)
+
+  let _order
+  if (order === 'asc' || order === 'desc') {
+    _order = order
+  }
+  else {
+    // toggle previous order
+    _order = object.order !== 'asc' ? 'asc' : 'desc'
+
+    data = setIn(data, dataPath.concat(['order']), _order)
+  }
+
+  if (object.type === 'array') {
+    return updateIn(data, dataPath.concat(['items']), (items) =>{
+      const ordered = items.slice(0)
+      const compare = _order === 'desc' ? compareDesc : compareAsc
+
+      ordered.sort((a, b) => compare(a.value, b.value))
+
+      return ordered
+    })
+  }
+  else { // object.type === 'object'
+    return updateIn(data, dataPath.concat(['props']), (props) => {
+      const orderedProps = props.slice(0)
+      const compare = _order === 'desc' ? compareDesc : compareAsc
+
+      orderedProps.sort((a, b) => compare(a.name, b.name))
+
+      return orderedProps
+    })
+  }
+}
+
+/**
+ * Expand or collapse an item or property
+ * @param {JSONData} data
+ * @param {Path} path
+ * @param {boolean} expand
+ * @return {JSONData}
+ */
+export function expand (data, path, expand) {
+  console.log('expand', path, expand)
+
+  const dataPath = toDataPath(data, path)
+
+  return setIn(data, dataPath.concat(['expanded']), expand)
+}
+
+/**
+ * Convert a path of a JSON object into a path in the corresponding data model
+ * @param {JSONData} data
+ * @param {Path} path
+ * @return {Path} dataPath
+ * @private
+ */
+export function toDataPath (data, path) {
+  if (path.length === 0) {
+    return []
+  }
+
+  let index
+  if (data.type === 'array') {
+    // index of an array
+    index = path[0]
+
+    return ['items', index].concat(toDataPath(data.items[index], path.slice(1)))
+  }
+  else {
+    // object property. find the index of this property
+    index = data.props.findIndex(prop => prop.name === path[0])
+
+    return ['props', index, 'value'].concat(toDataPath(data.props[index].value, path.slice(1)))
+  }
+}
+
+/**
+ * Convert a JSON object into the internally used data model
+ * @param {Path} path
+ * @param {Object | Array | string | number | boolean | null} json
+ * @param {function(path: Path)} expand
+ * @return {JSONData}
+ */
+export function jsonToData (path, json, expand) {
+  if (Array.isArray(json)) {
+    return {
+      type: 'array',
+      expanded: expand(path),
+      items: json.map((child, index) => jsonToData(path.concat(index), child, expand))
+    }
+  }
+  else if (isObject(json)) {
+    return {
+      type: 'object',
+      expanded: expand(path),
+      props: Object.keys(json).map(name => {
+        return {
+          name,
+          value: jsonToData(path.concat(name), json[name], expand)
+        }
+      })
+    }
+  }
+  else {
+    return {
+      type: 'value',
+      value: json
+    }
+  }
+}
+
+/**
+ * Convert the internal data model to a regular JSON object
+ * @param {JSONData} data
+ * @return {Object | Array | string | number | boolean | null} json
+ */
+export function dataToJson (data) {
+  switch (data.type) {
+    case 'array':
+      return data.items.map(dataToJson)
+
+    case 'object':
+      const object = {}
+
+      data.props.forEach(prop => {
+        object[prop.name] = dataToJson(prop.value)
+      })
+
+      return object
+
+    default: // type 'string' or 'value'
+      return data.value
+  }
+}
+
+
+/**
+ * Create a new data entry
+ * @param {JSONDataType} [type='value']
+ * @return {JSONData}
+ */
+export function createDataEntry (type) {
+  if (type === 'array') {
+    return {
+      type,
+      expanded: true,
+      items: []
+    }
+  }
+  else if (type === 'object') {
+    return {
+      type,
+      expanded: true,
+      props: []
+    }
+  }
+  else {
+    return {
+      type,
+      value: ''
+    }
+  }
+}
+
+/**
+ * Convert an entry into a different type. When possible, data is retained
+ * @param {JSONData} entry
+ * @param {JSONDataType} type
+ * @return {JSONData}
+ */
+export function convertDataEntry (entry, type) {
+  const convertedEntry = createDataEntry(type)
+
+  // convert contents from old value to new value where possible
+  if (type === 'value' && entry.type === 'string') {
+    convertedEntry.value = stringConvert(entry.value)
+  }
+
+  if (type === 'string' && entry.type === 'value') {
+    convertedEntry.value = entry.value + ''
+  }
+
+  if (type === 'object' && entry.type === 'array') {
+    convertedEntry.props = entry.items.map((item, index) => {
+      return {
+        name: index + '',
+        value: item
+      }
+    })
+  }
+
+  if (type === 'array' && entry.type === 'object') {
+    convertedEntry.items = entry.props.map(prop => prop.value)
+  }
+
+  return convertedEntry
+}
\ No newline at end of file
diff --git a/src/typedef.js b/src/typedef.js
index afedba2..fe6cba8 100644
--- a/src/typedef.js
+++ b/src/typedef.js
@@ -1,27 +1,31 @@
 
 /**
  * @typedef {{
- *   type: string,
+ *   type: 'array',
  *   expanded: boolean?,
  *   menu: boolean?,
- *   props: Array.<{name: string, value: Data}>?
+ *   props: Array.<{name: string, value: JSONData}>?
  * }} ObjectData
  *
  * @typedef {{
- *   type: string,
+ *   type: 'object',
  *   expanded: boolean?,
  *   menu: boolean?,
- *   items: Data[]?
+ *   items: JSONData[]?
  * }} ArrayData
  *
  * @typedef {{
- *   type: string,
+ *   type: 'value' | 'string',
  *   expanded: boolean?,
  *   menu: boolean?,
  *   value: *?
  * }} ValueData
  *
- * @typedef {ObjectData | ArrayData | ValueData} Data
+ * @typedef {Array.<string | number>} Path
+ *
+ * @typedef {ObjectData | ArrayData | ValueData} JSONData
+ *
+ * @typedef {'object' | 'array' | 'value' | 'string'} JSONDataType
  *
  * @typedef {{
  *
@@ -29,6 +33,6 @@
  *
  * @typedef {{
  *   name: string?,
- *   expand: function (path: Array.<string | number>)?
+ *   expand: function (path: Path)?
  * }} SetOptions
  */
\ No newline at end of file