diff --git a/lib/webpack/markdownLoader.js b/lib/webpack/markdownLoader.js
index 76148e721b..f73f7b74c1 100644
--- a/lib/webpack/markdownLoader.js
+++ b/lib/webpack/markdownLoader.js
@@ -78,7 +78,7 @@ module.exports = function (src) {
     `<template>\n` +
       `<div class="content">${html}</div>\n` +
     `</template>\n` +
-    hoistedTags.join('\n')
+    (hoistedTags || []).join('\n')
   )
   cache.set(key, res)
   return res