diff --git a/build/build.js b/build/build.js
index 563861373..0de786828 100644
--- a/build/build.js
+++ b/build/build.js
@@ -22,7 +22,10 @@ async function build(opts) {
     .rollup({
       input: opts.input,
       plugins: (opts.plugins || []).concat([
-        buble(),
+        buble({
+          transforms: {
+            dangerousForOf: true
+          }}),
         commonjs(),
         nodeResolve(),
         replace({
@@ -33,8 +36,8 @@ async function build(opts) {
       onwarn: function (message) {
         if (message.code === 'UNRESOLVED_IMPORT') {
           throw new Error(
-            `Could not resolve module ` + 
-            message.source + 
+            `Could not resolve module ` +
+            message.source +
             `. Try running 'npm install' or using rollup's 'external' option if this is an external dependency. ` +
             `Module ${message.source} is imported in ${message.importer}`
             )