diff --git a/themes/chameleon/scripts/sitemap/generator.js b/themes/chameleon/scripts/sitemap/generator.js
index bb23f5d..a0b113a 100644
--- a/themes/chameleon/scripts/sitemap/generator.js
+++ b/themes/chameleon/scripts/sitemap/generator.js
@@ -2,7 +2,6 @@
 
 const micromatch = require('micromatch')
 const template = require('./template')
-const moment = require('moment')
 
 const isMatch = (path, patterns) => {
   if (patterns && patterns.length) {
@@ -31,12 +30,6 @@ module.exports = function (locals) {
     .sort((a, b) => {
       return b.date - a.date
     })
-    // https://github.com/pyyzcwg2833/hexo-generator-sitemap/commit/a92dbbb83cc39ff60d43faa5cd688a56574a3889
-    .map((post) => ({
-      ...post,
-      date: moment(post.date).format('YYYY-MM-DD[T00:00:00.000Z]'),
-      updated: post.updated ? moment(post.updated).format('YYYY-MM-DD[T00:00:00.000Z]') : false
-    }))
 
   // configuration dictionary
   const xmlConfig = {
diff --git a/themes/chameleon/scripts/sitemap/template.js b/themes/chameleon/scripts/sitemap/template.js
index 25a1370..213f39c 100644
--- a/themes/chameleon/scripts/sitemap/template.js
+++ b/themes/chameleon/scripts/sitemap/template.js
@@ -15,7 +15,6 @@ module.exports = function (config) {
   })
 
   env.addFilter('formatDate', str => {
-    if (typeof str === 'string') return str.substring(0, 10)
     return moment(str).format('YYYY-MM-DD[T00:00:00.000Z]').substring(0, 10)
   })