576520
平常开启后无论怎么操作都不会出事或报错，但几乎每天早上睡觉起来再开网站就会出现 “TypeError: Cannot set property 'username' of undefined.”报错，但有时又不会。 请帮我看看哪里出错了~
var url = require("url");
var queryString = require("querystring");
var express = require('express');
var router = express.Router();
var flag = false;
var mongo = require('mongodb');
var monk = require('monk');
var db = monk('localhost:27017/Users');
router.get('/', function(req, res, next) {
var username = ''
var collection = db.get("userdata");
var stringA = req.originalUrl
var UID = stringA.substr(stringA.indexOf("?")+5)
if(UID){
collection.find({
"UID" : UID
},function(err,docs){
if(err){console.log(err)}
else {
username=docs[0].username
}
});
setTimeout(function(){
res.render('blog',{ username : username });
},200)
}
else { res.render('blog',{ username : '' });}
});
\n```
这是blog.ejs引用username代码
```html
<body data-username="<%= username %>">
这是网站nightcatsama.com