diff --git a/lib/rollup.js b/lib/rollup.js
index ec2c65e..31ba766 100644
--- a/lib/rollup.js
+++ b/lib/rollup.js
@@ -230,6 +230,10 @@ exports.rollupTree = function(loader, tree, entryPoints, traceOpts, compileOpts,
     return rollup.rollup({
       entry: entryPoint,
       external: aliasedExternals,
+      acorn: {
+            allowReserved: true,
+            ecmaVersion: 8
+        },
       plugins: [{
         resolveId: function(id, importer, options) {
           var resolved = importer ? tree[importer].depMap[id] : id;