diff --git a/build/build.js b/build/build.js
index 808450e..12f48b1 100644
--- a/build/build.js
+++ b/build/build.js
@@ -57,7 +57,6 @@ function createBundle ({ name, env, entry, format }) {
     const code = bundle.generate(options).code
     if (/min$/.test(name)) {
       const minified = uglify.minify(code, {
-        fromString: true,
         output: {
           preamble: banner,
           ascii_only: true, // eslint-disable-line camelcase