diff --git a/lib/webpack/createBaseConfig.js b/lib/webpack/createBaseConfig.js
index 0ea83c411c..cd09e2749a 100644
--- a/lib/webpack/createBaseConfig.js
+++ b/lib/webpack/createBaseConfig.js
@@ -70,10 +70,18 @@ module.exports = function createBaseConfig ({
         })
 
   if (!siteConfig.evergreen) {
+    const libDir = path.join(__dirname, '..')
     config.module
       .rule('js')
         .test(/\.js$/)
-        .exclude.add(/node_modules/).end()
+        .exclude.add(filepath => {
+          // Always transpile lib directory
+          if (filepath.startsWith(libDir)) {
+            return false
+          }
+          // Don't transpile node_modules
+          return /node_modules/.test(filepath)
+        }).end()
         .use('buble-loader')
           .loader('buble-loader')
           .options({