feat: add updated date

post.updated variable is not used because it's the time 'hexo generate' is executed,
post.updated includes non-content update.

themes/typing/languages/default.yml

@@ -18,3 +18,4 @@ rss_feed: RSS Feed
 category: Category
 tag: Tag
 date_published: Published Date
+date_updated: Last Updated

themes/typing/languages/en.yml

@@ -18,3 +18,4 @@ rss_feed: RSS Feed
 category: Category
 tag: Tag
 date_published: Published Date
+date_updated: Last Updated

themes/typing/layout/_partial/article.ejs

@@ -23,6 +23,12 @@
     </div>
     <footer class="article-footer">
       <ul class="article-meta">
+    <% if (post.lastUpdated) { %>
+        <li>
+          <span class="label"><%= __('date_updated') %>:</span>
+          <%- partial('post/updated-date', {class_name: 'article-date', date_format: 'D MMM YYYY'}) %>
+        </li>
+    <% } %>
         <li>
           <span class="label"><%= __('date_published') %>:</span>
           <%- partial('post/date', {class_name: 'article-date', date_format: 'D MMM YYYY'}) %>

themes/typing/layout/_partial/post/updated-date.ejs

@@ -0,0 +1,5 @@
+<%/* User-specified updated date */%>
+<%/* default post.updated is (almost) always is the time 'hexo generate' is executed */%>
+<a href="<%- url_for(post.path) %>" class="<%= class_name %>">
+  <time datetime="<%= date_xml(post.lastUpdated) %>" itemprop="dateUpdated"><%= date(post.lastUpdated, date_format) %></time>
+</a>