diff --git a/lib/build.js b/lib/build.js
index 307a06a4..c747f988 100644
--- a/lib/build.js
+++ b/lib/build.js
@@ -9,7 +9,7 @@ function webpackConfig(dir, additionalConfig) {
   var babelOpts = {cacheDirectory: true};
   if (!fs.existsSync(path.join(process.cwd(), '.babelrc'))) {
     babelOpts.presets = ["es2015"];
-    babelOptsplugins = [
+    babelOpts.plugins = [
       "transform-class-properties",
       "transform-object-assign",
       "transform-object-rest-spread"