diff --git a/package.json b/package.json
index 7ce4107..b6bb733 100644
--- a/package.json
+++ b/package.json
@@ -19,7 +19,7 @@
   "bugs": "https://github.com/josdejong/jsoneditor/issues",
   "scripts": {
     "build": "gulp",
-    "test": "ava test/*.test.js test/**/*.test.js",
+    "test": "ava test/*.test.js test/**/*.test.js --verbose",
     "watch": "gulp watch"
   },
   "dependencies": {
diff --git a/src/TreeMode.js b/src/TreeMode.js
index cb37f72..08b0495 100644
--- a/src/TreeMode.js
+++ b/src/TreeMode.js
@@ -1,7 +1,8 @@
 import { h, Component } from 'preact'
 
-import { setIn, updateIn, getIn, deleteIn, cloneDeep } from './utils/objectUtils'
-import { compareAsc, compareDesc, last } from './utils/arrayUtils'
+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/typeUtils'
 import bindMethods from './utils/bindMethods'
diff --git a/src/utils/immutabilityHelpers.js b/src/utils/immutabilityHelpers.js
index 62ffe82..5b78ba0 100644
--- a/src/utils/immutabilityHelpers.js
+++ b/src/utils/immutabilityHelpers.js
@@ -1,5 +1,16 @@
 'use strict';
 
+/**
+ * Immutability helpers
+ *
+ * inspiration:
+ *
+ * https://www.npmjs.com/package/seamless-immutable
+ * https://www.npmjs.com/package/ih
+ * https://www.npmjs.com/package/mutatis
+ */
+
+
 /**
  * helper function to get a nested property in an object or array
  *
diff --git a/src/utils/objectUtils.js b/src/utils/objectUtils.js
index ab4de1e..bad35b3 100644
--- a/src/utils/objectUtils.js
+++ b/src/utils/objectUtils.js
@@ -1,12 +1,6 @@
 import { isObject } from  './typeUtils'
 
 
-// inspiration:
-//
-// https://www.npmjs.com/package/seamless-immutable
-// https://www.npmjs.com/package/ih
-// https://www.npmjs.com/package/mutatis
-
 // TODO: unit test clone
 
 /**
@@ -58,138 +52,3 @@ export function cloneDeep (value) {
     return value
   }
 }
-
-// TODO: unit test getIn
-
-/**
- * helper function to get a nested property in an object or array
- *
- * @param {Object | Array} object
- * @param {Array.<string | number>} path
- * @return {* | undefined} Returns the field when found, or undefined when the
- *                         path doesn't exist
- */
-export function getIn (object, path) {
-  let value = object
-  let i = 0
-
-  while(i < path.length) {
-    if (Array.isArray(value) || isObject(value)) {
-      value = value[path[i]]
-    }
-    else {
-      value = undefined
-    }
-
-    i++
-  }
-
-  return value
-}
-
-// TODO: unit test setIn
-
-/**
- * helper function to replace a nested property in an object with a new value
- * without mutating the object itself.
- *
- * @param {Object | Array} object
- * @param {Array.<string | number>} path
- * @param {*} value
- * @return {Object | Array} Returns a new, updated object or array
- */
-export function setIn (object, path, value) {
-  if (path.length === 0) {
-    return value
-  }
-
-  const key = path[0]
-  let updated
-  if (typeof key === 'string' && !isObject(object)) {
-    updated = {}  // change into an object
-  }
-  else if (typeof key === 'number' && !Array.isArray(object)) {
-    updated = []  // change into an array
-  }
-  else {
-    updated = clone(object)
-  }
-
-  updated[key] = setIn(updated[key], path.slice(1), value)
-
-  return updated
-}
-
-// TODO: unit test updateIn
-
-/**
- * helper function to replace a nested property in an object with a new value
- * without mutating the object itself.
- *
- * @param {Object | Array} object
- * @param {Array.<string | number>} path
- * @param {function} callback
- * @return {Object | Array} Returns a new, updated object or array
- */
-export function updateIn (object, path, callback) {
-  if (path.length === 0) {
-    return callback(object)
-  }
-
-  const key = path[0]
-  let updated
-  if (typeof key === 'string' && !isObject(object)) {
-    updated = {}  // change into an object
-  }
-  else if (typeof key === 'number' && !Array.isArray(object)) {
-    updated = []  // change into an array
-  }
-  else {
-    updated = clone(object)
-  }
-
-  updated[key] = updateIn(updated[key], path.slice(1), callback)
-
-  return updated
-}
-
-// TODO: unit test deleteIn
-
-/**
- * helper function to delete a nested property in an object
- * without mutating the object itself.
- *
- * @param {Object | Array} object
- * @param {Array.<string | number>} path
- * @return {Object | Array} Returns a new, updated object or array
- */
-export function deleteIn (object, path) {
-  if (path.length === 0) {
-    return object
-  }
-
-  if (path.length === 1) {
-    const key = path[0]
-    const updated = clone(object)
-    if (Array.isArray(updated)) {
-      updated.splice(key, 1)
-    }
-    else {
-      delete updated[key]
-    }
-
-    return updated
-  }
-
-  const key = path[0]
-  const child = object[key]
-  if (Array.isArray(child) || isObject(child)) {
-    const updated = clone(object)
-    updated[key] = deleteIn(child, path.slice(1))
-    return updated
-  }
-  else {
-    // child property doesn't exist. just do nothing
-    return object
-  }
-}