diff --git a/public/js/extra.js b/public/js/extra.js
index f449bed19..d4a6c5cd2 100644
--- a/public/js/extra.js
+++ b/public/js/extra.js
@@ -1,5 +1,6 @@
 var hljs = require('highlight.js');
 var PDFObject = require('pdfobject');
+var S = require('string');
 
 //auto update last change
 var createtime = null;
diff --git a/webpack.config.js b/webpack.config.js
index 85e3a0056..cad356fb6 100644
--- a/webpack.config.js
+++ b/webpack.config.js
@@ -15,7 +15,8 @@ module.exports = {
             emojify: "emojify.js",
             io: "socket.io-client",
             LZString: "lz-string",
-            key: "keymaster"
+            key: "keymaster",
+            Viz: "viz.js"
         }),
         new webpack.DefinePlugin({
             "require.specified": "require.resolve"