diff --git a/package.json b/package.json
index 94da9aaeb..769c2b037 100644
--- a/package.json
+++ b/package.json
@@ -11,7 +11,7 @@
     "ckeditor5-math",
     "katex"
   ],
-  "main": "src/index.js",
+  "main": "src/index.ts",
   "dependencies": {
     "ckeditor5": "41.2.0"
   },