node.js设置MongoDB时Connection stra

node版本8.8.1
mongodb版本3.4.10
connect-mongo版本0.8.2
express-session版本1.15.6

app.js中部分代码：

var express = require('express'),
    routes = require('./routes');
var path = require('path');
var favicon = require('serve-favicon');
var logger = require('morgan');
var cookieParser = require('cookie-parser');
var bodyParser = require('body-parser');
var session = require('express-session');
var MongoStore = require('connect-mongo')(session);

报错片段：

app.use(session({
    store: new MongoStore({
        db: settings.db
    }),
    secret: settings.cookieSecret
}));

修改为：

app.use(session({
    store: new MongoStore({
        url: 'mongodb://localhost/microblog'
    }),
    secret: settings.cookieSecret
}));

然后执行：sudo node app.js

参考网址：http://blog.csdn.net/lhwomg/article/details/73867326
http://cnodejs.org/topic/567a1120222744630726b244