事情的起因是我的同事
金果
问我：
- “你知道微信公众号文章的渲染方式吗？”
对此，我的反应是：
- “啊？”
金果继续问：
- “控制台的 Network 里没有发生任何请求，文章里的内容是怎么来的？”
说到这儿我好像大概理解她的意思，于是打开控制台的 Network 确认一下果真如此，文章中的内容并不是通过 http 请求获取的。
首先我想到的是：
- “会不会是服务器端渲染的？”
于是我找到请求得到的 html 文件却发现：
- “只有文章的标题是服务器端渲染的，那么文章的内容就只能在 js 文件中。”
我继续寻找请求得到的 js 文件却发现空空如也：
- “难道 js 文件都被缓存到 localStorage 里？！”
看到 Local Storage 里密密麻麻的 js 文件我心里一阵澎湃：这确实是一种可以尝试的前端加载性能优化的方式。
使用 localStorage 进行资源缓存的解决方案梳理
缓存更新机制
项目在迭代开发的过程中，难以避免需要更新资源文件，常用的方法有`文件名${md5}.js`或者在资源 url 后面加上特定后缀的方式 etc.，而在微信做法中以
MOON
pages/report.js
为例，其版本信息使用 key 为
MOON
pages/report.js_ver
的存储项保存：
__MOON__pages/report.js_ver: //res.wx.qq.com/mmbizwap/zh_CN/htmledition/js/pages/report3b8dd6.js
我们不直接使用这个 value 动态插入 script 节点来加载该文件，而是根据后端提供的配置信息，判断是选择使用缓存的
MOON
pages/report.js
文件，还是重新发起加载请求。
搭建更新代码的脚手架
（加载 combo 化）使用基于 localStorage 的缓存机制，就需要一个脚手架来管理资源文件的读取和写入，不难看出微信使用的是自己开发的脚手架
moon.js
，阅读其源码代价较大，暂不分析。
资源配置信息
前端在进行资源更新时需要后端提供一份依据供前端用于判断哪些资源需要更新，并且脚手架 moon.js 需要该资源配置信息才能正常工作，所以配置信息一定要在 moon.js 的 script 标签前输出：
window.moon_map = {"new_video/player.html.js":"//res.wx.qq.com/mmbizwap/zh_CN/htmledition/js/new_video/player.html3b8dd6.js","biz_wap/zepto/touch.js":"//res.wx.qq.com/mmbizwap/zh_CN/htmledition/js/biz_wap/zepto/touch34c264.js","biz_wap/zepto/event.js":"//res.wx.qq.com/mmbizwap/zh_CN/htmledition/js/biz_wap/zepto/event34c264.js","biz_wap/zepto/zepto.js":"//res.wx.qq.com/mmbizwap/zh_CN/htmledition/js/biz_wap/zepto/zepto34c264.js","page/pages/video.css":"//res.wx.qq.com/mmbizwap/zh_CN/htmledition/style/page/pages/video.css3b8dd6.js","a/appdialog_confirm.html.js":"//res.wx.qq.com/mmbizwap/zh_CN/htmledition/js/a/appdialog_confirm.html34f0d8.js","widget/wx_profile_dialog_primary.css":"//res.wx.qq.com/mmbizwap/zh_CN/htmledition/style/widget/wx_profile_dialog_primary.css34f0d8.js","appmsg/emotion/caret.js":"//res.wx.qq.com/mmbizwap/zh_CN/htmledition/js/appmsg/emotion/caret278965.js","new_video/player.js":"//res.wx.qq.com/mmbizwap/zh_CN/htmledition/js/new_video/player3b8ecd.js","a/appdialog_confirm.js":"//res.wx.qq.com/mmbizwap/zh_CN/htmledition/js/a/appdialog_confirm34c32a.js","biz_wap/jsapi/cardticket.js":"//res.wx.qq.com/mmbizwap/zh_CN/htmledition/js/biz_wap/jsapi/cardticket34c264.js","biz_common/utils/emoji_panel_data.js":"//res.wx.qq.com/mmbizwap/zh_CN/htmledition/js/biz_common/utils/emoji_panel_data3518c6.js",
"biz_common/utils/emoji_data.js":"//res.wx.qq.com/mmbizwap/zh_CN/htmledition/js/biz_common/utils/emoji_data3518c6.js","appmsg/emotion/textarea.js":"//res.wx.qq.com/mmbizwap/zh_CN/htmledition/js/appmsg/emotion/textarea353f34.js","appmsg/emotion/nav.js":"//res.wx.qq.com/mmbizwap/zh_CN/htmledition/js/appmsg/emotion/nav278965.js","appmsg/emotion/common.js":"//res.wx.qq.com/mmbizwap/zh_CN/htmledition/js/appmsg/emotion/common3518c6.js","appmsg/emotion/slide.js":"//res.wx.qq.com/mmbizwap/zh_CN/htmledition/js/appmsg/emotion/slide2a9cd9.js","pages/loadscript.js":"//res.wx.qq.com/mmbizwap/zh_CN/htmledition/js/pages/loadscript39aac6.js","pages/music_report_conf.js":"//res.wx.qq.com/mmbizwap/zh_CN/htmledition/js/pages/music_report_conf39aac6.js","pages/report.js":"//res.wx.qq.com/mmbizwap/zh_CN/htmledition/js/pages/report3b8dd6.js","pages/player_adaptor.js":"//res.wx.qq.com/mmbizwap/zh_CN/htmledition/js/pages/player_adaptor39d6ee.js","pages/music_player.js":"//res.wx.qq.com/mmbizwap/zh_CN/htmledition/js/pages/music_player3af14e.js","appmsg/emotion/dom.js":"//res.wx.qq.com/mmbizwap/zh_CN/htmledition/js/appmsg/emotion/dom31ff31.js","appmsg/comment_tpl.html.js":"//res.wx.qq.com/mmbizwap/zh_CN/htmledition/js/appmsg/comment_tpl.html36c376.js","biz_wap/utils/fakehash.js":"//res.wx.qq.com/mmbizwap/zh_CN/htmledition/js/biz_wap/utils/fakehash38c7af.js","biz_common/utils/wxgspeedsdk.js":"//res.wx.qq.com/mmbizwap/zh_CN/htmledition/js/biz_common/utils/wxgspeedsdk3518c6.js","a/video.js":"//res.wx.qq.com/mmbizwap/zh_CN/htmledition/js/a/video3b8ecd.js","a/sponsor.js":"//res.wx.qq.com/mmbizwap/zh_CN/htmledition/js/a/sponsor3b86a9.js","a/app_card.js":"//res.wx.qq.com/mmbizwap/zh_CN/htmledition/js/a/app_card393ef4.js","a/ios.js":"//res.wx.qq.com/mmbizwap/zh_CN/htmledition/js/a/ios393966.js","a/android.js":"//res.wx.qq.com/mmbizwap/zh_CN/htmledition/js/a/android393966.js","a/profile.js":"//res.wx.qq.com/mmbizwap/zh_CN/htmledition/js/a/profile31ff31.js","a/cpc_a_tpl.html.js":"//res.wx.qq.com/mmbizwap/zh_CN/htmledition/js/a/cpc_a_tpl.html3b540a.js","a/sponsor_a_tpl.html.js":"//res.wx.qq.com/mmbizwap/zh_CN/htmledition/js/a/sponsor_a_tpl.html36c7cf.js","a/a_tpl.html.js":"//res.wx.qq.com/mmbizwap/zh_CN/htmledition/js/a/a_tpl.html3b86a9.js","a/mpshop.js":"//res.wx.qq.com/mmbizwap/zh_CN/htmledition/js/a/mpshop311179.js","a/wxopen_card.js":"//res.wx.qq.com/mmbizwap/zh_CN/htmledition/js/a/wxopen_card3a95b8.js","a/card.js":"//res.wx.qq.com/mmbizwap/zh_CN/htmledition/js/a/card311179.js","biz_wap/utils/position.js":"//res.wx.qq.com/mmbizwap/zh_CN/htmledition/js/biz_wap/utils/position34c264.js","a/a_report.js":"//res.wx.qq.com/mmbizwap/zh_CN/htmledition/js/a/a_report393966.js","appmsg/my_comment_tpl.html.js":"//res.wx.qq.com/mmbizwap/zh_CN/htmledition/js/appmsg/my_comment_tpl.html36906d.js","appmsg/cmt_tpl.html.js":"//res.wx.qq.com/mmbizwap/zh_CN/htmledition/js/appmsg/cmt_tpl.html369d00.js","sougou/a_tpl.html.js":"//res.wx.qq.com/mmbizwap/zh_CN/htmledition/js/sougou/a_tpl.html2c6e7c.js","appmsg/emotion/emotion.js":"//res.wx.qq.com/mmbizwap/zh_CN/htmledition/js/appmsg/emotion/emotion353f34.js","biz_wap/utils/wapsdk.js":"//res.wx.qq.com/mmbizwap/zh_CN/htmledition/js/biz_wap/utils/wapsdk34c264.js","biz_common/utils/report.js":"//res.wx.qq.com/mmbizwap/zh_CN/htmledition/js/biz_common/utils/report3518c6.js","appmsg/open_url_with_webview.js":"//res.wx.qq.com/mmbizwap/zh_CN/htmledition/js/appmsg/open_url_with_webview3145f0.js","biz_common/utils/http.js":"//res.wx.qq.com/mmbizwap/zh_CN/htmledition/js/biz_common/utils/http3518c6.js","biz_common/utils/cookie.js":"//res.wx.qq.com/mmbizwap/zh_CN/htmledition/js/biz_common/utils/cookie3518c6.js","appmsg/topic_tpl.html.js":"//res.wx.qq.com/mmbizwap/zh_CN/htmledition/js/appmsg/topic_tpl.html31ff31.js","pages/weapp_tpl.html.js":"//res.wx.qq.com/mmbizwap/zh_CN/htmledition/js/pages/weapp_tpl.html36906d.js","biz_common/utils/monitor.js":"//res.wx.qq.com/mmbizwap/zh_CN/htmledition/js/biz_common/utils/monitor3518c6.js","appmsg/weapp_common.js":"//res.wx.qq.com/mmbizwap/zh_CN/htmledition/js/appmsg/weapp_common3af55a.js","pages/voice_tpl.html.js":"//res.wx.qq.com/mmbizwap/zh_CN/htmledition/js/pages/voice_tpl.html38518d.js","pages/kugoumusic_ctrl.js":"//res.wx.qq.com/mmbizwap/zh_CN/htmledition/js/pages/kugoumusic_ctrl393e3a.js","pages/qqmusic_ctrl.js":"//res.wx.qq.com/mmbizwap/zh_CN/htmledition/js/pages/qqmusic_ctrl39b68c.js","pages/voice_component.js":
