diff --git a/src/JSONEditor.scss b/src/components/JSONEditor.scss
similarity index 95%
rename from src/JSONEditor.scss
rename to src/components/JSONEditor.scss
index e37db82..90c1b9e 100644
--- a/src/JSONEditor.scss
+++ b/src/components/JSONEditor.scss
@@ -1,4 +1,4 @@
-@import './styles.scss';
+@import '../styles.scss';
 
 .jsoneditor {
   border: 1px solid $theme-color;
diff --git a/src/JSONEditor.svelte b/src/components/JSONEditor.svelte
similarity index 90%
rename from src/JSONEditor.svelte
rename to src/components/JSONEditor.svelte
index 9c22294..304af46 100644
--- a/src/JSONEditor.svelte
+++ b/src/components/JSONEditor.svelte
@@ -6,34 +6,33 @@
     insertBefore,
     removeAll,
     replace
-  } from './operations.js'
+  } from '../logic/operations.js'
   import {
     STATE_EXPANDED,
     STATE_LIMIT,
     SCROLL_DURATION,
     STATE_PROPS
-  } from './constants.js'
-  import { createHistory } from './history.js'
+  } from '../constants.js'
+  import { createHistory } from '../logic/history.js'
   import JSONNode from './JSONNode.svelte'
   import {
     createPathsMap,
     createSelectionFromOperations,
     expandSelection
-  } from './selection.js'
-  import { isContentEditableDiv } from './utils/domUtils.js'
+  } from '../logic/selection.js'
+  import { isContentEditableDiv } from '../utils/domUtils.js'
   import {
     getIn,
     setIn,
     updateIn
-  } from './utils/immutabilityHelpers.js'
-  import { compileJSONPointer, parseJSONPointer } from './utils/jsonPointer.js'
-  import { keyComboFromEvent } from './utils/keyBindings.js'
-  import { search, searchNext, searchPrevious } from './utils/search.js'
-  import { immutableJSONPatch } from './utils/immutableJSONPatch'
+  } from '../utils/immutabilityHelpers.js'
+  import { compileJSONPointer, parseJSONPointer } from '../utils/jsonPointer.js'
+  import { keyComboFromEvent } from '../utils/keyBindings.js'
+  import { search, searchNext, searchPrevious } from '../logic/search.js'
+  import { immutableJSONPatch } from '../utils/immutableJSONPatch'
   import { initial, last, cloneDeep } from 'lodash-es'
-  import jump from './assets/jump.js/src/jump.js'
-  import { expandPath, stateUtils } from './utils/stateUtils.js'
-  import { getNextKeys, patchProps } from './utils/updateProps.js'
+  import jump from '../assets/jump.js/src/jump.js'
+  import { expandPath, syncState, getNextKeys, patchProps } from '../logic/documentState.js'
   import Menu from './Menu.svelte'
 
   let divContents
@@ -49,7 +48,7 @@
   $: hasSelectionContents = selection != null && selection.paths != null
   $: hasClipboardContents = clipboard != null && selection != null
 
-  $: state = stateUtils(doc, state, [], (path) => path.length < 1)
+  $: state = syncState(doc, state, [], (path) => path.length < 1)
 
   let showSearch = false
   let searchText = ''
@@ -63,11 +62,11 @@
   let historyState = history.getState()
 
   export function expand (callback = () => true) {
-    state = stateUtils(doc, state, [], callback, true)
+    state = syncState(doc, state, [], callback, true)
   }
 
   export function collapse (callback = () => false) {
-    state = stateUtils(doc, state, [], callback, true)
+    state = syncState(doc, state, [], callback, true)
   }
 
   export function get() {
@@ -168,7 +167,7 @@
         const parentPath = initial(selection.beforePath)
         const beforeKey = last(selection.beforePath)
         const props = getIn(state, parentPath.concat(STATE_PROPS))
-        const nextKeys = getNextKeys(props, parentPath, beforeKey, true)
+        const nextKeys = getNextKeys(props, beforeKey, true)
         const operations = insertBefore(doc, selection.beforePath, clipboard, nextKeys)
         const newSelection = createSelectionFromOperations(operations)
 
@@ -183,7 +182,7 @@
         const parentPath = initial(lastPath)
         const beforeKey = last(lastPath)
         const props = getIn(state, parentPath.concat(STATE_PROPS))
-        const nextKeys = getNextKeys(props, parentPath, beforeKey, true)
+        const nextKeys = getNextKeys(props, beforeKey, true)
         const operations = replace(doc, selection.paths, clipboard, nextKeys)
         const newSelection = createSelectionFromOperations(operations)
 
@@ -200,7 +199,7 @@
       const parentPath = initial(lastPath)
       const beforeKey = last(lastPath)
       const props = getIn(state, parentPath.concat(STATE_PROPS))
-      const nextKeys = getNextKeys(props, parentPath, beforeKey, false)
+      const nextKeys = getNextKeys(props, beforeKey, false)
 
       const operations = duplicate(doc, selection.paths, nextKeys)
       const newSelection = createSelectionFromOperations(operations)
@@ -318,7 +317,7 @@
   function handleExpand (path, expanded, recursive = false) {
     if (recursive) {
       state = updateIn(state, path, (childState) => {
-        return stateUtils(getIn(doc, path), childState, [], () => expanded, true)
+        return syncState(getIn(doc, path), childState, [], () => expanded, true)
       })
     } else {
       state = setIn(state, path.concat(STATE_EXPANDED), expanded, true)
@@ -471,4 +470,4 @@
   </div>
 </div>
 
-<style src="JSONEditor.scss"></style>
+<style src="./JSONEditor.scss"></style>
diff --git a/src/JSONNode.scss b/src/components/JSONNode.scss
similarity index 99%
rename from src/JSONNode.scss
rename to src/components/JSONNode.scss
index 51896f8..acfaf70 100644
--- a/src/JSONNode.scss
+++ b/src/components/JSONNode.scss
@@ -1,4 +1,4 @@
-@import './styles.scss';
+@import '../styles.scss';
 
 .json-node {
   position: relative;
diff --git a/src/JSONNode.svelte b/src/components/JSONNode.svelte
similarity index 96%
rename from src/JSONNode.svelte
rename to src/components/JSONNode.svelte
index 804b427..85eff22 100644
--- a/src/JSONNode.svelte
+++ b/src/components/JSONNode.svelte
@@ -1,6 +1,6 @@
 <script>
   import { debounce, isEqual } from 'lodash-es'
-  import { rename } from './operations.js'
+  import { rename } from '../logic/operations.js'
   import {
     DEBOUNCE_DELAY,
     DEFAULT_LIMIT,
@@ -10,8 +10,8 @@
     STATE_SEARCH_PROPERTY,
     STATE_SEARCH_VALUE,
     INDENTATION_WIDTH
-  } from './constants.js'
-  import { singleton } from './singleton.js'
+  } from '../constants.js'
+  import { singleton } from '../singleton.js'
   import {
     getPlainText,
     isAppendNodeSelector,
@@ -19,14 +19,14 @@
     isChildOfButton,
     isContentEditableDiv,
     setPlainText
-  } from './utils/domUtils.js'
+  } from '../utils/domUtils.js'
   import Icon from 'svelte-awesome'
   import { faCaretDown, faCaretRight } from '@fortawesome/free-solid-svg-icons'
   import classnames from 'classnames'
-  import { findUniqueName } from './utils/stringUtils.js'
-  import { isUrl, stringConvert, valueType } from './utils/typeUtils'
-  import { compileJSONPointer } from './utils/jsonPointer'
-  import { getNextKeys } from './utils/updateProps.js'
+  import { findUniqueName } from '../utils/stringUtils.js'
+  import { isUrl, stringConvert, valueType } from '../utils/typeUtils'
+  import { compileJSONPointer } from '../utils/jsonPointer'
+  import { getNextKeys } from '../logic/documentState.js'
 
   export let key = undefined // only applicable for object properties
   export let value
@@ -125,7 +125,7 @@
 
   function handleUpdateKey (oldKey, newKey) {
     const newKeyUnique = findUniqueName(newKey, value)
-    const nextKeys = getNextKeys(props, path, key, false)
+    const nextKeys = getNextKeys(props, key, false)
 
     onPatch(rename(path, oldKey, newKeyUnique, nextKeys))
   }
@@ -505,4 +505,4 @@
   {/if}
 </div>
 
-<style src="JSONNode.scss"></style>
+<style src="./JSONNode.scss"></style>
diff --git a/src/Menu.scss b/src/components/Menu.scss
similarity index 97%
rename from src/Menu.scss
rename to src/components/Menu.scss
index db31058..c9ce489 100644
--- a/src/Menu.scss
+++ b/src/components/Menu.scss
@@ -1,4 +1,4 @@
-@import './styles.scss';
+@import '../styles.scss';
 
 .menu {
   font-family: $font-family-menu;
diff --git a/src/Menu.svelte b/src/components/Menu.svelte
similarity index 98%
rename from src/Menu.svelte
rename to src/components/Menu.svelte
index 789677e..33feae6 100644
--- a/src/Menu.svelte
+++ b/src/components/Menu.svelte
@@ -115,4 +115,4 @@
   {/if}
 </div>
 
-<style src="Menu.scss"></style>
+<style src="./Menu.scss"></style>
diff --git a/src/SearchBox.scss b/src/components/SearchBox.scss
similarity index 97%
rename from src/SearchBox.scss
rename to src/components/SearchBox.scss
index 9abcd40..30e6dc3 100644
--- a/src/SearchBox.scss
+++ b/src/components/SearchBox.scss
@@ -1,4 +1,4 @@
-@import './styles.scss';
+@import '../styles.scss';
 
 $search-size: 24px;
 
diff --git a/src/SearchBox.svelte b/src/components/SearchBox.svelte
similarity index 93%
rename from src/SearchBox.svelte
rename to src/components/SearchBox.svelte
index a1c1d21..41abda5 100644
--- a/src/SearchBox.svelte
+++ b/src/components/SearchBox.svelte
@@ -2,8 +2,8 @@
   import { debounce } from 'lodash-es'
   import Icon from 'svelte-awesome'
   import { faSearch, faChevronDown, faChevronUp, faTimes } from '@fortawesome/free-solid-svg-icons'
-  import { DEBOUNCE_DELAY } from './constants.js'
-  import { keyComboFromEvent } from './utils/keyBindings.js'
+  import { DEBOUNCE_DELAY } from '../constants.js'
+  import { keyComboFromEvent } from '../utils/keyBindings.js'
 
   export let text = ''
   let inputText = ''
@@ -84,4 +84,4 @@
   </form>
 </div>
 
-<style src="SearchBox.scss"></style>
+<style src="./SearchBox.scss"></style>
diff --git a/src/logic/documentState.js b/src/logic/documentState.js
new file mode 100644
index 0000000..7d0afc0
--- /dev/null
+++ b/src/logic/documentState.js
@@ -0,0 +1,210 @@
+import { initial, isEqual, isNumber, last, uniqueId } from 'lodash-es'
+import {
+  DEFAULT_LIMIT,
+  STATE_EXPANDED,
+  STATE_LIMIT,
+  STATE_PROPS
+} from '../constants.js'
+import { deleteIn, getIn, insertAt, setIn } from '../utils/immutabilityHelpers.js'
+import { parseJSONPointer } from '../utils/jsonPointer.js'
+import { isObject, isObjectOrArray } from '../utils/typeUtils.js'
+
+/**
+ * Sync a state object with the doc it belongs to: update props, limit, and expanded state
+ *
+ * @param {JSON} doc
+ * @param {JSON | undefined} state
+ * @param {Path} path
+ * @param {function (path: Path) : boolean} expand
+ * @param {boolean} [forceRefresh=false] if true, force refreshing the expanded state
+ * @returns {JSON | undefined}
+ */
+export function syncState (doc, state = undefined, path, expand, forceRefresh = false) {
+  // TODO: this function can be made way more efficient if we pass prevState:
+  //  when immutable, we can simply be done already when the state === prevState
+
+  if (isObject(doc)) {
+    const updatedState = {}
+
+    updatedState[STATE_PROPS] = updateProps(doc, state && state[STATE_PROPS])
+
+    updatedState[STATE_EXPANDED] = (state && !forceRefresh)
+      ? state[STATE_EXPANDED]
+      : expand(path)
+
+    if (updatedState[STATE_EXPANDED]) {
+      Object.keys(doc).forEach(key => {
+        const childDocument = doc[key]
+        if (isObjectOrArray(childDocument)) {
+          const childState = state && state[key]
+          updatedState[key] = syncState(childDocument, childState, path.concat(key), expand, forceRefresh)
+        }
+      })
+    }
+
+    return updatedState
+  }
+
+  if (Array.isArray(doc)) {
+    const updatedState = []
+
+    updatedState[STATE_EXPANDED] = (state && !forceRefresh)
+      ? state[STATE_EXPANDED]
+      : expand(path)
+
+    // note that we reset the limit when the state is not expanded
+    updatedState[STATE_LIMIT] = (state && updatedState[STATE_EXPANDED])
+      ? state[STATE_LIMIT]
+      : DEFAULT_LIMIT
+
+    if (updatedState[STATE_EXPANDED]) {
+      for (let i = 0; i < Math.min(doc.length, updatedState[STATE_LIMIT]); i++) {
+        const childDocument = doc[i]
+        if (isObjectOrArray(childDocument)) {
+          const childState = state && state[i]
+          updatedState[i] = syncState(childDocument, childState, path.concat(i), expand, forceRefresh)
+        }
+      }
+    }
+
+    return updatedState
+  }
+
+  // primitive values have no state
+  return undefined
+}
+
+/**
+ * Expand all nodes on given path
+ * @param {JSON} state
+ * @param {Path} path
+ * @return {JSON} returns the updated state
+ */
+// TODO: write unit tests for expandPath
+export function expandPath (state, path) {
+  let updatedState = state
+
+  for (let i = 1; i < path.length; i++) {
+    const partialPath = path.slice(0, i)
+    // FIXME: setIn has to create object first
+    updatedState = setIn(updatedState, partialPath.concat(STATE_EXPANDED), true, true)
+
+    // if needed, enlarge the limit such that the search result becomes visible
+    const key = path[i]
+    if (isNumber(key)) {
+      const limit = getIn(updatedState, partialPath.concat(STATE_LIMIT)) || DEFAULT_LIMIT
+      if (key > limit) {
+        const newLimit = Math.ceil(key / DEFAULT_LIMIT) * DEFAULT_LIMIT
+        updatedState = setIn(updatedState, partialPath.concat(STATE_LIMIT), newLimit, true)
+      }
+    }
+  }
+
+  return updatedState
+}
+
+export function updateProps (value, prevProps) {
+  if (!isObject(value)) {
+    return undefined
+  }
+
+  // copy the props that still exist
+  const props = prevProps
+    ? prevProps.filter(item => value[item.key] !== undefined)
+    : []
+
+  // add new props
+  const prevKeys = new Set(props.map(item => item.key))
+  Object.keys(value).forEach(key => {
+    if (!prevKeys.has(key)) {
+      props.push({
+        id: uniqueId(),
+        key
+      })
+    }
+  })
+
+  return props
+}
+
+// TODO: write unit tests
+// TODO: split this function in smaller functions
+export function patchProps (state, operations) {
+  let updatedState = state
+
+  operations.map(operation => {
+    if (operation.op === 'move') {
+      if (isEqual(
+        initial(parseJSONPointer(operation.from)),
+        initial(parseJSONPointer(operation.path))
+      )) {
+        // move inside the same object
+        const pathFrom = parseJSONPointer(operation.from)
+        const pathTo = parseJSONPointer(operation.path)
+        const parentPath = initial(pathFrom)
+        const props = getIn(updatedState, parentPath.concat(STATE_PROPS))
+
+        if (props) {
+          const oldKey = last(pathFrom)
+          const newKey = last(pathTo)
+          const oldIndex = props.findIndex(item => item.key === oldKey)
+
+          if (oldIndex !== -1) {
+            if (oldKey !== newKey) {
+              // A property is renamed.
+
+              // in case the new key shadows an existing key, remove the existing key
+              const newIndex = props.findIndex(item => item.key === newKey)
+              if (newIndex !== -1) {
+                const updatedProps = deleteIn(props, [newIndex])
+                updatedState = setIn(updatedState, parentPath.concat([STATE_PROPS]), updatedProps, true)
+              }
+
+              // Rename the key in the object's props so it maintains its identity and hence its index
+              updatedState = setIn(updatedState, parentPath.concat([STATE_PROPS, oldIndex, 'key']), newKey, true)
+            } else {
+              // operation.from and operation.path are the same:
+              // property is moved but stays the same -> move it to the end of the props
+              const oldProp = props[oldIndex]
+              const updatedProps = insertAt(deleteIn(props, [oldIndex]), [props.length - 1], oldProp)
+
+              updatedState = setIn(updatedState, parentPath.concat([STATE_PROPS]), updatedProps, true)
+            }
+          }
+        }
+      }
+    }
+
+    if (operation.op === 'add' || operation.op === 'copy') {
+      const pathTo = parseJSONPointer(operation.path)
+      const parentPath = initial(pathTo)
+      const key = last(pathTo)
+      const props = getIn(updatedState, parentPath.concat(STATE_PROPS))
+      if (props) {
+        const index = props.findIndex(item => item.key === key)
+        if (index === -1) {
+          const newProp = {
+            id: uniqueId(),
+            key
+          }
+          const updatedProps = insertAt(props, [props.length], newProp)
+
+          updatedState = setIn(updatedState, parentPath.concat([STATE_PROPS]), updatedProps, true)
+        }
+      }
+    }
+  })
+
+  return updatedState
+}
+
+export function getNextKeys(props, key, includeKey = false) {
+  if (props) {
+    const index = props.findIndex(prop => prop.key === key)
+    if (index !== -1) {
+      return props.slice(index + (includeKey ? 0 : 1)).map(prop => prop.key)
+    }
+  }
+
+  return []
+}
diff --git a/src/utils/stateUtils.test.js b/src/logic/documentState.test.js
similarity index 64%
rename from src/utils/stateUtils.test.js
rename to src/logic/documentState.test.js
index 7d8a297..fe1b3c8 100644
--- a/src/utils/stateUtils.test.js
+++ b/src/logic/documentState.test.js
@@ -5,9 +5,9 @@ import {
   STATE_LIMIT,
   STATE_PROPS
 } from '../constants.js'
-import { stateUtils } from './stateUtils.js'
+import { syncState, updateProps } from './documentState.js'
 
-describe('syncState', () => {
+describe('documentState', () => {
   it('syncState', () => {
     const document = {
       array: [1, 2, {c: 6}],
@@ -19,7 +19,7 @@ describe('syncState', () => {
       return path.length <= 1
     }
 
-    const state = stateUtils(document, undefined, [], expand)
+    const state = syncState(document, undefined, [], expand)
 
     const expectedState = {}
     expectedState[STATE_EXPANDED] = true
@@ -46,5 +46,20 @@ describe('syncState', () => {
     assert.deepStrictEqual(state, expectedState)
   })
 
-  // TODO: write more unit tests for stateUtils
+  it('updateProps (1)', () => {
+    const props1 = updateProps({b: 2})
+    assert.deepStrictEqual(props1.map(item => item.key), ['b'])
+
+    const props2 = updateProps({a: 1, b: 2}, props1)
+    assert.deepStrictEqual(props2.map(item => item.key), ['b', 'a'])
+    assert.deepStrictEqual(props2[0], props1[0]) // b must still have the same id
+  })
+
+  it('updateProps (2)', () => {
+    const props1 = updateProps({a: 1, b: 2})
+    const props2 = updateProps({a: 1, b: 2}, props1)
+    assert.deepStrictEqual(props2, props1)
+  })
+
+  // TODO: write more unit tests
 })
diff --git a/src/history.js b/src/logic/history.js
similarity index 100%
rename from src/history.js
rename to src/logic/history.js
diff --git a/src/operations.js b/src/logic/operations.js
similarity index 97%
rename from src/operations.js
rename to src/logic/operations.js
index e73377b..2c55f4a 100644
--- a/src/operations.js
+++ b/src/logic/operations.js
@@ -1,7 +1,7 @@
 import { first, initial, last, pickBy } from 'lodash-es'
-import { getIn } from './utils/immutabilityHelpers'
-import { compileJSONPointer } from './utils/jsonPointer'
-import { findUniqueName } from './utils/stringUtils'
+import { getIn } from '../utils/immutabilityHelpers'
+import { compileJSONPointer } from '../utils/jsonPointer'
+import { findUniqueName } from '../utils/stringUtils'
 
 /**
  * Create a JSONPatch for an insert operation.
diff --git a/src/utils/search.js b/src/logic/search.js
similarity index 97%
rename from src/utils/search.js
rename to src/logic/search.js
index 14372cb..606bbce 100644
--- a/src/utils/search.js
+++ b/src/logic/search.js
@@ -1,7 +1,7 @@
 import { isEqual, isNumber } from 'lodash-es'
 import { STATE_SEARCH_PROPERTY, STATE_SEARCH_VALUE } from '../constants.js'
-import { existsIn, setIn } from './immutabilityHelpers.js'
-import { valueType } from './typeUtils.js'
+import { existsIn, setIn } from '../utils/immutabilityHelpers.js'
+import { valueType } from '../utils/typeUtils.js'
 
 
 /**
diff --git a/src/selection.js b/src/logic/selection.js
similarity index 92%
rename from src/selection.js
rename to src/logic/selection.js
index 4c7b212..38d26c3 100644
--- a/src/selection.js
+++ b/src/logic/selection.js
@@ -1,8 +1,8 @@
 import { isEqual } from 'lodash-es'
-import { STATE_PROPS } from './constants.js'
-import { getIn } from './utils/immutabilityHelpers.js'
-import { compileJSONPointer, parseJSONPointer } from './utils/jsonPointer.js'
-import { isObject } from './utils/typeUtils.js'
+import { STATE_PROPS } from '../constants.js'
+import { getIn } from '../utils/immutabilityHelpers.js'
+import { compileJSONPointer, parseJSONPointer } from '../utils/jsonPointer.js'
+import { isObject } from '../utils/typeUtils.js'
 
 /**
  * Expand a selection start and end into an array containing all paths
diff --git a/src/selection.test.js b/src/logic/selection.test.js
similarity index 93%
rename from src/selection.test.js
rename to src/logic/selection.test.js
index 7d6a699..5ac5cce 100644
--- a/src/selection.test.js
+++ b/src/logic/selection.test.js
@@ -1,6 +1,6 @@
 import assert from 'assert'
 import { expandSelection } from './selection.js'
-import { stateUtils } from './utils/stateUtils.js'
+import { syncState } from './documentState.js'
 
 describe ('selection', () => {
   const doc = {
@@ -11,7 +11,7 @@ describe ('selection', () => {
     "nill": null,
     "bool": false
   }
-  const state = stateUtils(doc, undefined, [], () => true)
+  const state = syncState(doc, undefined, [], () => true)
 
   it('should expand a selection (object)', () => {
     const start = ['obj', 'arr', '2', 'last']
diff --git a/src/main.js b/src/main.js
index eaa8048..0f94155 100644
--- a/src/main.js
+++ b/src/main.js
@@ -1,4 +1,4 @@
-import JSONEditor from './JSONEditor.svelte'
+import JSONEditor from './components/JSONEditor.svelte'
 
 export default function jsoneditor (config) {
 	return new JSONEditor(config)
diff --git a/src/utils/stateUtils.js b/src/utils/stateUtils.js
deleted file mode 100644
index 69dc035..0000000
--- a/src/utils/stateUtils.js
+++ /dev/null
@@ -1,104 +0,0 @@
-import { isNumber } from 'lodash-es'
-import {
-  DEFAULT_LIMIT,
-  STATE_EXPANDED,
-  STATE_LIMIT,
-  STATE_PROPS
-} from '../constants.js'
-import { getIn, setIn } from './immutabilityHelpers.js'
-import { isObject, isObjectOrArray } from './typeUtils.js'
-import { updateProps } from './updateProps.js'
-
-/**
- * Sync a state object with the doc it belongs to: update props, limit, and expanded state
- *
- * @param {JSON} doc
- * @param {JSON | undefined} state
- * @param {Path} path
- * @param {function (path: Path) : boolean} expand
- * @param {boolean} [forceRefresh=false] if true, force refreshing the expanded state
- * @returns {JSON | undefined}
- */
-export function stateUtils (doc, state = undefined, path, expand, forceRefresh = false) {
-  // TODO: this function can be made way more efficient if we pass prevState:
-  //  when immutable, we can simply be done already when the state === prevState
-
-  if (isObject(doc)) {
-    const updatedState = {}
-
-    updatedState[STATE_PROPS] = updateProps(doc, state && state[STATE_PROPS])
-
-    updatedState[STATE_EXPANDED] = (state && !forceRefresh)
-      ? state[STATE_EXPANDED]
-      : expand(path)
-
-    if (updatedState[STATE_EXPANDED]) {
-      Object.keys(doc).forEach(key => {
-        const childDocument = doc[key]
-        if (isObjectOrArray(childDocument)) {
-          const childState = state && state[key]
-          updatedState[key] = stateUtils(childDocument, childState, path.concat(key), expand, forceRefresh)
-        }
-      })
-    }
-
-    return updatedState
-  }
-
-  if (Array.isArray(doc)) {
-    const updatedState = []
-
-    updatedState[STATE_EXPANDED] = (state && !forceRefresh)
-      ? state[STATE_EXPANDED]
-      : expand(path)
-
-    // note that we reset the limit when the state is not expanded
-    updatedState[STATE_LIMIT] = (state && updatedState[STATE_EXPANDED])
-      ? state[STATE_LIMIT]
-      : DEFAULT_LIMIT
-
-    if (updatedState[STATE_EXPANDED]) {
-      for (let i = 0; i < Math.min(doc.length, updatedState[STATE_LIMIT]); i++) {
-        const childDocument = doc[i]
-        if (isObjectOrArray(childDocument)) {
-          const childState = state && state[i]
-          updatedState[i] = stateUtils(childDocument, childState, path.concat(i), expand, forceRefresh)
-        }
-      }
-    }
-
-    return updatedState
-  }
-
-  // primitive values have no state
-  return undefined
-}
-
-/**
- * Expand all nodes on given path
- * @param {JSON} state
- * @param {Path} path
- * @return {JSON} returns the updated state
- */
-// TODO: write unit tests for expandPath
-export function expandPath (state, path) {
-  let updatedState = state
-
-  for (let i = 1; i < path.length; i++) {
-    const partialPath = path.slice(0, i)
-    // FIXME: setIn has to create object first
-    updatedState = setIn(updatedState, partialPath.concat(STATE_EXPANDED), true, true)
-
-    // if needed, enlarge the limit such that the search result becomes visible
-    const key = path[i]
-    if (isNumber(key)) {
-      const limit = getIn(updatedState, partialPath.concat(STATE_LIMIT)) || DEFAULT_LIMIT
-      if (key > limit) {
-        const newLimit = Math.ceil(key / DEFAULT_LIMIT) * DEFAULT_LIMIT
-        updatedState = setIn(updatedState, partialPath.concat(STATE_LIMIT), newLimit, true)
-      }
-    }
-  }
-
-  return updatedState
-}
diff --git a/src/utils/updateProps.js b/src/utils/updateProps.js
deleted file mode 100644
index b3a2a41..0000000
--- a/src/utils/updateProps.js
+++ /dev/null
@@ -1,111 +0,0 @@
-import { initial, isEqual, last, uniqueId } from 'lodash-es'
-import { STATE_PROPS } from '../constants.js'
-import { deleteIn, getIn, insertAt, setIn } from './immutabilityHelpers.js'
-import { parseJSONPointer } from './jsonPointer.js'
-import { isObject } from './typeUtils.js'
-
-export function updateProps (value, prevProps) {
-  if (!isObject(value)) {
-    return undefined
-  }
-
-  // copy the props that still exist
-  const props = prevProps
-    ? prevProps.filter(item => value[item.key] !== undefined)
-    : []
-
-  // add new props
-  const prevKeys = new Set(props.map(item => item.key))
-  Object.keys(value).forEach(key => {
-    if (!prevKeys.has(key)) {
-      props.push({
-        id: uniqueId(),
-        key
-      })
-    }
-  })
-
-  return props
-}
-
-// TODO: write unit tests
-// TODO: split this function in smaller functions
-export function patchProps (state, operations) {
-  let updatedState = state
-
-  operations.map(operation => {
-    if (operation.op === 'move') {
-      if (isEqual(
-        initial(parseJSONPointer(operation.from)),
-        initial(parseJSONPointer(operation.path))
-      )) {
-        // move inside the same object
-        const pathFrom = parseJSONPointer(operation.from)
-        const pathTo = parseJSONPointer(operation.path)
-        const parentPath = initial(pathFrom)
-        const props = getIn(updatedState, parentPath.concat(STATE_PROPS))
-
-        if (props) {
-          const oldKey = last(pathFrom)
-          const newKey = last(pathTo)
-          const oldIndex = props.findIndex(item => item.key === oldKey)
-
-          if (oldIndex !== -1) {
-            if (oldKey !== newKey) {
-              // A property is renamed.
-
-              // in case the new key shadows an existing key, remove the existing key
-              const newIndex = props.findIndex(item => item.key === newKey)
-              if (newIndex !== -1) {
-                const updatedProps = deleteIn(props, [newIndex])
-                updatedState = setIn(updatedState, parentPath.concat([STATE_PROPS]), updatedProps, true)
-              }
-
-              // Rename the key in the object's props so it maintains its identity and hence its index
-              updatedState = setIn(updatedState, parentPath.concat([STATE_PROPS, oldIndex, 'key']), newKey, true)
-            } else {
-              // operation.from and operation.path are the same:
-              // property is moved but stays the same -> move it to the end of the props
-              const oldProp = props[oldIndex]
-              const updatedProps = insertAt(deleteIn(props, [oldIndex]), [props.length - 1], oldProp)
-
-              updatedState = setIn(updatedState, parentPath.concat([STATE_PROPS]), updatedProps, true)
-            }
-          }
-        }
-      }
-    }
-
-    if (operation.op === 'add' || operation.op === 'copy') {
-      const pathTo = parseJSONPointer(operation.path)
-      const parentPath = initial(pathTo)
-      const key = last(pathTo)
-      const props = getIn(updatedState, parentPath.concat(STATE_PROPS))
-      if (props) {
-        const index = props.findIndex(item => item.key === key)
-        if (index === -1) {
-          const newProp = {
-            id: uniqueId(),
-            key
-          }
-          const updatedProps = insertAt(props, [props.length], newProp)
-
-          updatedState = setIn(updatedState, parentPath.concat([STATE_PROPS]), updatedProps, true)
-        }
-      }
-    }
-  })
-
-  return updatedState
-}
-
-export function getNextKeys(props, parentPath, key, includeKey = false) {
-  if (props) {
-    const index = props.findIndex(prop => prop.key === key)
-    if (index !== -1) {
-      return props.slice(index + (includeKey ? 0 : 1)).map(prop => prop.key)
-    }
-  }
-
-  return []
-}
\ No newline at end of file
diff --git a/src/utils/updateProps.test.js b/src/utils/updateProps.test.js
deleted file mode 100644
index 53262b4..0000000
--- a/src/utils/updateProps.test.js
+++ /dev/null
@@ -1,21 +0,0 @@
-import assert from 'assert'
-import { updateProps } from './updateProps.js'
-
-describe('updateProps', () => {
-
-  it('updateProps (1)', () => {
-    const props1 = updateProps({b: 2})
-    assert.deepStrictEqual(props1.map(item => item.key), ['b'])
-
-    const props2 = updateProps({a: 1, b: 2}, props1)
-    assert.deepStrictEqual(props2.map(item => item.key), ['b', 'a'])
-    assert.deepStrictEqual(props2[0], props1[0]) // b must still have the same id
-  })
-
-  it('updateProps (2)', () => {
-    const props1 = updateProps({a: 1, b: 2})
-    const props2 = updateProps({a: 1, b: 2}, props1)
-    assert.deepStrictEqual(props2, props1)
-  })
-
-})