diff --git a/src/index.ts b/src/index.ts
index 6425405..21cb2af 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -35,5 +35,9 @@ class DiffEngine {
   }
 }
 
+// CommonJS export
+module.exports = DiffEngine
+module.exports.default = DiffEngine
+
 // ES module export
-export = DiffEngine
+export default DiffEngine