diff --git a/public/js/index.js b/public/js/index.js
index d28f4d6..27b0295 100644
--- a/public/js/index.js
+++ b/public/js/index.js
@@ -80,6 +80,7 @@ import { preventXSS } from './render'
 import Editor from './lib/editor'
 
 import getUIElements from './lib/editor/ui-elements'
+import modeType from './lib/editor/modeType'
 
 var defaultTextHeight = 20
 var viewportMargin = 20
@@ -226,17 +227,6 @@ var supportExtraTags = [
     }
   }
 ]
-window.modeType = {
-  edit: {
-    name: 'edit'
-  },
-  view: {
-    name: 'view'
-  },
-  both: {
-    name: 'both'
-  }
-}
 var statusType = {
   connected: {
     msg: 'CONNECTED',
diff --git a/public/js/lib/editor/modeType.js b/public/js/lib/editor/modeType.js
new file mode 100644
index 0000000..f321210
--- /dev/null
+++ b/public/js/lib/editor/modeType.js
@@ -0,0 +1,11 @@
+export default {
+  edit: {
+    name: 'edit'
+  },
+  view: {
+    name: 'view'
+  },
+  both: {
+    name: 'both'
+  }
+}
diff --git a/public/js/syncscroll.js b/public/js/syncscroll.js
index c227f83..ad21e57 100644
--- a/public/js/syncscroll.js
+++ b/public/js/syncscroll.js
@@ -5,6 +5,7 @@
 import markdownitContainer from 'markdown-it-container'
 
 import { md } from './extra'
+import modeType from './lib/editor/modeType'
 
 function addPart (tokens, idx) {
   if (tokens[idx].map && tokens[idx].level === 0) {
@@ -228,7 +229,7 @@ function buildMapInner (callback) {
 let viewScrollingTimer = null
 
 export function syncScrollToEdit (event, preventAnimate) {
-  if (window.currentMode !== window.modeType.both || !window.syncscroll || !editArea) return
+  if (window.currentMode !== modeType.both || !window.syncscroll || !editArea) return
   if (window.preventSyncScrollToEdit) {
     if (typeof window.preventSyncScrollToEdit === 'number') {
       window.preventSyncScrollToEdit--
@@ -310,7 +311,7 @@ function viewScrollingTimeoutInner () {
 let editScrollingTimer = null
 
 export function syncScrollToView (event, preventAnimate) {
-  if (window.currentMode !== window.modeType.both || !window.syncscroll || !viewArea) return
+  if (window.currentMode !== modeType.both || !window.syncscroll || !viewArea) return
   if (window.preventSyncScrollToView) {
     if (typeof preventSyncScrollToView === 'number') {
       window.preventSyncScrollToView--