diff --git a/source/index.ts b/source/index.ts
index 86e7ca4..1b7cf38 100644
--- a/source/index.ts
+++ b/source/index.ts
@@ -247,3 +247,7 @@ Object.defineProperties(is, {
 });
 
 export default is;
+
+// For CommonJS default export support
+module.exports = is;
+module.exports.default = is;