feat(openGraph): add post's published time to meta tag

* Rename function name to camel case (standardjs)
* Skip timezone conversion, but not using the date() helper
* Open Graph tag is based on Wordpress Yoast, noticed through
https://dvt.name/2019/06/03/hacking-the-casio-f-91w-to-handle-1000-psi/

themes/typing/layout/_partial/head.ejs

@@ -22,8 +22,8 @@
   <title><% if (title) { %><%= title %> | <% } %><%= config.title %></title>
   <meta name="viewport" content="width=device-width, initial-scale=1, maximum-scale=1">
   <%/* Add Open Graph meta tags for easier sharing on social networking sites */%>
-  <%/* Modified for cloudinary compatibility */%>
-  <%- open_graph_cloudinary() %>
+  <%/* Modified from original source for compatibility with my blog */%>
+  <%- openGraph() %>
   <% if (theme.rss) { %>
     <link rel="alternate" href="<%- theme.rss %>" title="<%= config.title %>" type="application/atom+xml">
   <% } %>

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

@@ -1,3 +1,4 @@
 <a href="<%- url_for(post.path) %>" class="<%= class_name %>">
-  <time datetime="<%= date_xml(post.date) %>" itemprop="datePublished"><%= date(post.date, date_format) %></time>
+  <%/* Date format is specified to skip timezone conversion */%>
+  <time datetime="<%= date(post.date, 'YYYY-MM-DD[T]HH:mm:ss.SSS[Z]') %>" itemprop="datePublished"><%= date(post.date, date_format) %></time>
 </a>

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

@@ -1,5 +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>
+  <time datetime="<%= date(post.lastUpdated, 'YYYY-MM-DD[T]HH:mm:ss.SSS[Z]') %>" itemprop="dateUpdated"><%= date(post.lastUpdated, date_format) %></time>
 </a>

themes/typing/scripts/openGraph.js

@@ -48,7 +48,8 @@ function openGraphHelper (options = {}) {
   const url = options.url || this.url
   const siteName = options.site_name || config.title
   const twitterCard = options.twitter_card || 'summary'
-  const updated = options.updated !== false ? options.updated || page.updated : false
+  const published = page.date || false
+  const updated = page.lastUpdated || false
   const language = options.language || page.lang || page.language || config.language
   let result = ''
 
@@ -116,9 +117,18 @@ function openGraphHelper (options = {}) {
     result += og('og:image', path, false)
   })
 
+
+  if (published) {
+    if ((moment.isMoment(published) || moment.isDate(published)) && !isNaN(published.valueOf())) {
+      // Skip timezone conversion
+      result += og('article:published_time', moment(published).format('YYYY-MM-DD[T]HH:mm:ss.SSS[Z]'))
+    }
+  }
+
   if (updated) {
     if ((moment.isMoment(updated) || moment.isDate(updated)) && !isNaN(updated.valueOf())) {
-      result += og('og:updated_time', updated.toISOString())
+      result += og('article:modified_time', moment(updated).format('YYYY-MM-DD[T]HH:mm:ss.SSS[Z]'))
+      result += og('og:updated_time', moment(updated).format('YYYY-MM-DD[T]HH:mm:ss.SSS[Z]'))
     }
   }
 
@@ -158,4 +168,4 @@ function openGraphHelper (options = {}) {
   return result.trim()
 }
 
-hexo.extend.helper.register('open_graph_cloudinary', openGraphHelper)
+hexo.extend.helper.register('openGraph', openGraphHelper)