mongodb - node中往mongo中插入数据的时候，明明插入成功了，但是会返回错误信息？
exports.adduser = function(db) {
return function(req, res) {
// Get our form values. These rely on the "name" attributes
var userName = req.body.username;
var userEmail = req.body.useremail;
// Set our collection
var collection = db.get('users');
// Submit to the DB
collection.insert({
"username": userName,
"email": userEmail
}, function(err, doc) {
if (err) {
res.send("There was a problem adding the information to the database.");
} else {
// If it worked, set the header so the address bar doesn't still say /adduser
res.location("userlist");
res.redirect("userlist");
}
});
}
}插入函数如上，我提交表单之后，查看数据库中是有数据的。但是会打印处if (err)的错误信息？这是什么原因造成的，我如果把res.location("userlist");res.redirect("userlist");移到if err里会报错，不会跳转
