#140

frontend/src/components/TopNav.tsx

@@ -65,7 +65,7 @@ export default (({ user }: Props) => {
   const postCount = tag?.postCount ?? 0
 
   const wikiPageFlg = Boolean (/^\/wiki\/(?!new|changes)[^\/]+/.test (location.pathname) && wikiId)
-  const wikiTitle = location.pathname.split ('/')[2]
+  const wikiTitle = location.pathname.split ('/')[2] ?? ''
   const menu: Menu = [
       { name: '広場', to: '/posts', subMenu: [
 	  { name: '一覧', to: '/posts' },