newpagetags is list

src/client/js/app.js

@@ -66,7 +66,7 @@ let pageContent = '';
 let markdown = '';
 let slackChannels;
 let currentPageTags = [];
-let newPageTags = '';
+let newPageTags = [];
 if (mainContent !== null) {
   pageId = mainContent.getAttribute('data-page-id') || null;
   pageRevisionId = mainContent.getAttribute('data-page-revision-id');