fix: handle null post.updated

atom.xml

@@ -21,7 +21,7 @@
     <link href="{{ post.permalink | uriencode }}"/>
     <id>{{ post.permalink | uriencode }}</id>
     <published>{{ post.date.toISOString() }}</published>
-    <updated>{{ post.updated.toISOString() }}</updated>
+    <updated>{% if post.updated %}{{ post.updated.toISOString() }}{% else %}{{ post.date.toISOString() }}{% endif %}</updated>
     {% if config.feed.content and post.content %}
     <content type="html"><![CDATA[{{ post.content | noControlChars | safe }}]]></content>
     {% endif %}

rss2.xml

@@ -15,7 +15,7 @@
     <atom:link href="{{ feed_url | uriencode }}" rel="self" type="application/rss+xml"/>
     {% if config.feed.hub %}<atom:link href="{{ config.feed.hub | uriencode }}" rel="hub"/>{% endif %}
     <description>{{ config.description }}</description>
-    <pubDate>{{ posts.first().updated.toDate().toUTCString() }}</pubDate>
+    <pubDate>{% if posts.first().updated %}{{ posts.first().updated.toDate().toUTCString() }}{% else %}{{ posts.first().date.toDate().toUTCString() }}{% endif %}</pubDate>
     <generator>http://hexo.io/</generator>
     {% for post in posts.toArray() %}
     <item>

test/index.js

@@ -52,7 +52,8 @@ describe('Feed generator', () => {
     await Post.insert([
       {source: 'foo', slug: 'foo', content: '<h6>TestHTML</h6>', date: 1e8},
       {source: 'bar', slug: 'bar', date: 1e8 + 1},
-      {source: 'baz', slug: 'baz', title: 'With Image', image: 'test.png', date: 1e8 - 1}
+      {source: 'baz', slug: 'baz', title: 'With Image', image: 'test.png', date: 1e8 - 1},
+      {source: 'date', slug: 'date', title: 'date', date: 1e8 - 2, updated: undefined}
     ]);
     posts = Post.sort('-date');
     locals = hexo.locals.toObject();
@@ -375,6 +376,25 @@ describe('Feed generator', () => {
       feed_url: 'http://localhost/atom.xml'
     }));
   });
+
+  it('no updated date', () => {
+    hexo.config.optional_updated = true;
+    hexo.config.feed = {
+      type: 'atom',
+      path: 'atom.xml'
+    };
+    hexo.config = Object.assign(hexo.config, urlConfig);
+    const feedCfg = hexo.config.feed;
+    const result = generator(locals, feedCfg.type, feedCfg.path);
+
+    const $ = cheerio.load(result.data);
+    const updated = $('feed>entry:nth-of-type(4)>updated').text();
+    const date = $('feed>entry:nth-of-type(4)>published').text();
+
+    updated.should.eql(date);
+
+    hexo.config.optional_updated = false;
+  });
 });
 
 it('No posts', () => {