diff --git a/webpack.config.dev.js b/webpack.config.dev.js
index 4ead5cdd..6c80d7a9 100644
--- a/webpack.config.dev.js
+++ b/webpack.config.dev.js
@@ -1,4 +1,4 @@
 const config = require('./webpack.config.js');
 
-config.entry.test_runner = ['./web/test/runner'];
+config.entry.test_runner = ['babel-polyfill', './web/test/runner'];
 module.exports = config;
diff --git a/webpack.config.js b/webpack.config.js
index dea9eb62..3170b0a2 100644
--- a/webpack.config.js
+++ b/webpack.config.js
@@ -5,7 +5,7 @@ module.exports = {
   devtool: 'source-map',
   entry: {
     index: ['babel-polyfill', './web/app/index'],
-    sketcher: ['./web/app/sketcher']
+    sketcher: ['babel-polyfill', './web/app/sketcher']
   },
   output: {
     path: path.join(__dirname, 'dist/static'),