add order-by option

README.md

@@ -30,6 +30,7 @@ feed:
   content:
   content_limit: 140
   content_limit_delim: ' '
+  order_by: -date
 ```
 
 - **type** - Feed type. (atom/rss2)
@@ -39,3 +40,4 @@ feed:
 - **content** - (optional) set to 'true' to include the contents of the entire post in the feed.
 - **content_limit** - (optional) Default length of post content used in summary. Only used, if **content** setting is false and no custom post description present.
 - **content_limit_delim** - (optional) If **content_limit** is used to shorten post contents, only cut at the last occurrence of this delimiter before reaching the character limit. Not used by default.
+- **order_by** - Feed order-by. (Default: -date)

index.js

@@ -10,7 +10,8 @@ var config = hexo.config.feed = assign({
   hub: '',
   content: true,
   content_limit: 140,
-  content_limit_delim: ''
+  content_limit_delim: '',
+  order_by: '-date'
 }, hexo.config.feed);
 
 var type = config.type.toLowerCase();

lib/generator.js

@@ -24,7 +24,7 @@ module.exports = function(locals) {
   var feedConfig = config.feed;
   var template = feedConfig.type === 'rss2' ? rss2Tmpl : atomTmpl;
 
-  var posts = locals.posts.sort('-date');
+  var posts = locals.posts.sort(feedConfig.order_by);
   posts = posts.filter(function(post) {
     return post.draft !== true;
   });