add theme

themes/butterfly/scripts/helpers/series.js

@@ -0,0 +1,22 @@
+'use strict'
+
+hexo.extend.helper.register('groupPosts', function () {
+  const getGroupArray = array => {
+    return array.reduce((groups, item) => {
+      const key = item.series
+      if (key) {
+        groups[key] = groups[key] || []
+        groups[key].push(item)
+      }
+      return groups
+    }, {})
+  }
+
+  const sortPosts = posts => {
+    const { orderBy = 'date', order = 1 } = this.theme.aside.card_post_series
+    if (orderBy === 'title') return posts.sort('title', order)
+    return posts.sort('date', order)
+  }
+
+  return getGroupArray(sortPosts(this.site.posts))
+})