diff --git a/rollup.config.js b/rollup.config.js
index 736a913..2d903e6 100644
--- a/rollup.config.js
+++ b/rollup.config.js
@@ -29,7 +29,7 @@ export default {
 			commonjs(),
 
 			legacy && babel({
-				extensions: ['.js', '.html'],
+				extensions: ['.js', '.mjs', '.html', '.svelte'],
 				runtimeHelpers: true,
 				exclude: ['node_modules/@babel/**'],
 				presets: [