Update engine.js

lib/react/engine.js

@@ -15,7 +15,7 @@ const tree = dirTree('./react/')
 if (tree) {
   for (const index in tree.children) {
     const file = tree.children[index]
-    if (file.type === 'file') {
+    if (file.type === 'file' && file.extension === '.js') {
       if (!fs.existsSync(path.join(dist, 'react'))) {
         fs.mkdirSync(path.join(dist, 'react'), { recursive: true })
       }