diff --git a/src/TreeMode.js b/src/TreeMode.js
index 3e55616..ab0594c 100644
--- a/src/TreeMode.js
+++ b/src/TreeMode.js
@@ -18,7 +18,7 @@ export default class TreeMode extends Component {
     super(props)
 
     const expand = this.props.options && this.props.options.expand || TreeMode.expand
-    const data = jsonToData([], this.props.data || {}, expand)
+    const data = jsonToData(this.props.data || {}, expand, [])
 
     this.state = {
       options: {
@@ -266,7 +266,7 @@ export default class TreeMode extends Component {
    */
   set (json, options = {}) {
     const name = options && options.name || null // the root name
-    const data = jsonToData([], json, options.expand || TreeMode.expand)
+    const data = jsonToData(json, options.expand || TreeMode.expand, [])
 
     this.setState({
       options: setIn(this.state.options, ['name'], name),
diff --git a/src/jsonData.js b/src/jsonData.js
index 57cfb68..c828046 100644
--- a/src/jsonData.js
+++ b/src/jsonData.js
@@ -16,18 +16,17 @@ const expandAll = function (path) {
 
 /**
  * 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
+ * @param {function(path: Path)} [expand]
+ * @param {Path} [path=[]]
  * @return {JSONData}
  */
-// TODO: change signature to jsonToData(json [, expand=(path) => false [, path=[]]])
-export function jsonToData (path, json, expand) {
+export function jsonToData (json, expand = expandAll, path = []) {
   if (Array.isArray(json)) {
     return {
       type: 'Array',
       expanded: expand(path),
-      items: json.map((child, index) => jsonToData(path.concat(index), child, expand))
+      items: json.map((child, index) => jsonToData(child, expand, path.concat(index)))
     }
   }
   else if (isObject(json)) {
@@ -37,7 +36,7 @@ export function jsonToData (path, json, expand) {
       props: Object.keys(json).map(name => {
         return {
           name,
-          value: jsonToData(path.concat(name), json[name], expand)
+          value: jsonToData(json[name], expand, path.concat(name))
         }
       })
     }
@@ -120,7 +119,7 @@ export function patchData (data, patch) {
       switch (action.op) {
         case 'add': {
           const path = parseJSONPointer(action.path)
-          const newValue = jsonToData(path, action.value, expand)
+          const newValue = jsonToData(action.value, expand, path)
 
           // TODO: move setting type to jsonToData
           if (options && options.type) {
@@ -146,7 +145,7 @@ export function patchData (data, patch) {
 
         case 'replace': {
           const path = parseJSONPointer(action.path)
-          let newValue = jsonToData(path, action.value, expand)
+          let newValue = jsonToData(action.value, expand, path)
 
           // TODO: move setting type to jsonToData
           if (options && options.type) {
diff --git a/test/jsonData.test.js b/test/jsonData.test.js
index ceaa16b..74da9e6 100644
--- a/test/jsonData.test.js
+++ b/test/jsonData.test.js
@@ -241,7 +241,7 @@ test('jsonToData', t => {
     return true
   }
 
-  t.deepEqual(jsonToData([], JSON_EXAMPLE, expand), JSON_DATA_EXAMPLE)
+  t.deepEqual(jsonToData(JSON_EXAMPLE, expand, []), JSON_DATA_EXAMPLE)
 })
 
 test('dataToJson', t => {
@@ -302,7 +302,7 @@ test('jsonpatch add', t => {
     {op: 'add', path: '/obj/b', value: {foo: 'bar'}}
   ]
 
-  const data = jsonToData([], json, (path) => false)
+  const data = jsonToData(json)
   const result = patchData(data, patch)
   const patchedData = result.data
   const revert = result.revert
@@ -327,7 +327,7 @@ test('jsonpatch add: append to matrix', t => {
     {op: 'add', path: '/arr/-', value: 4}
   ]
 
-  const data = jsonToData([], json, (path) => false)
+  const data = jsonToData(json)
   const result = patchData(data, patch)
   const patchedData = result.data
   const revert = result.revert
@@ -354,7 +354,7 @@ test('jsonpatch remove', t => {
     {op: 'remove', path: '/arr/1'},
   ]
 
-  const data = jsonToData([], json, (path) => false)
+  const data = jsonToData(json)
   const result = patchData(data, patch)
   const patchedData = result.data
   const revert = result.revert
@@ -370,7 +370,7 @@ test('jsonpatch remove', t => {
   ])
 
   // test revert
-  const data2 = jsonToData([], patchedJson, (path) => false)
+  const data2 = jsonToData(patchedJson)
   const result2 = patchData(data2, revert)
   const patchedData2 = result2.data
   const revert2 = result2.revert
@@ -391,7 +391,7 @@ test('jsonpatch replace', t => {
     {op: 'replace', path: '/arr/1', value: 200},
   ]
 
-  const data = jsonToData([], json, (path) => false)
+  const data = jsonToData(json)
   const result = patchData(data, patch)
   const patchedData = result.data
   const revert = result.revert
@@ -407,7 +407,7 @@ test('jsonpatch replace', t => {
   ])
 
   // test revert
-  const data2 = jsonToData([], patchedJson, (path) => false)
+  const data2 = jsonToData(patchedJson)
   const result2 = patchData(data2, revert)
   const patchedData2 = result2.data
   const revert2 = result2.revert
@@ -430,7 +430,7 @@ test('jsonpatch copy', t => {
     {op: 'copy', from: '/obj', path: '/arr/2'},
   ]
 
-  const data = jsonToData([], json, (path) => false)
+  const data = jsonToData(json)
   const result = patchData(data, patch)
   const patchedData = result.data
   const revert = result.revert
@@ -445,7 +445,7 @@ test('jsonpatch copy', t => {
   ])
 
   // test revert
-  const data2 = jsonToData([], patchedJson, (path) => false)
+  const data2 = jsonToData(patchedJson)
   const result2 = patchData(data2, revert)
   const patchedData2 = result2.data
   const revert2 = result2.revert
@@ -467,7 +467,7 @@ test('jsonpatch move', t => {
     {op: 'move', from: '/obj', path: '/arr/2'},
   ]
 
-  const data = jsonToData([], json, (path) => false)
+  const data = jsonToData(json)
   const result = patchData(data, patch)
   const patchedData = result.data
   const revert = result.revert
@@ -482,7 +482,7 @@ test('jsonpatch move', t => {
   ])
 
   // test revert
-  const data2 = jsonToData([], patchedJson, (path) => false)
+  const data2 = jsonToData(patchedJson)
   const result2 = patchData(data2, revert)
   const patchedData2 = result2.data
   const revert2 = result2.revert
@@ -502,7 +502,7 @@ test('jsonpatch move and replace', t => {
     {op: 'move', from: '/obj', path: '/arr'},
   ]
 
-  const data = jsonToData([], json, (path) => false)
+  const data = jsonToData(json)
   const result = patchData(data, patch)
   const patchedData = result.data
   const revert = result.revert
@@ -517,7 +517,7 @@ test('jsonpatch move and replace', t => {
   ])
 
   // test revert
-  const data2 = jsonToData([], patchedJson, (path) => false)
+  const data2 = jsonToData(patchedJson)
   const result2 = patchData(data2, revert)
   const patchedData2 = result2.data
   const revert2 = result2.revert
@@ -540,7 +540,7 @@ test('jsonpatch test (ok)', t => {
     {op: 'add', path: '/added', value: 'ok'}
   ]
 
-  const data = jsonToData([], json, (path) => false)
+  const data = jsonToData(json)
   const result = patchData(data, patch)
   const patchedData = result.data
   const revert = result.revert
@@ -568,7 +568,7 @@ test('jsonpatch test (fail: path not found)', t => {
     {op: 'add', path: '/added', value: 'ok'}
   ]
 
-  const data = jsonToData([], json, (path) => false)
+  const data = jsonToData(json)
   const result = patchData(data, patch)
   const patchedData = result.data
   const revert = result.revert
@@ -594,7 +594,7 @@ test('jsonpatch test (fail: value not equal)', t => {
     {op: 'add', path: '/added', value: 'ok'}
   ]
 
-  const data = jsonToData([], json, (path) => false)
+  const data = jsonToData(json)
   const result = patchData(data, patch)
   const patchedData = result.data
   const revert = result.revert