diff --git a/scripts/rollup.config.js b/scripts/rollup.config.js
index e6a2d0f5..fad93e5a 100644
--- a/scripts/rollup.config.js
+++ b/scripts/rollup.config.js
@@ -48,6 +48,7 @@ export default [{
   output: {
     ...baseConfig.output,
     file: pkg.main,
+    intro: 'var window',
     format: 'cjs'
   },
   external: Object.keys(pkg.dependencies)