app.js

const express = require('express');
const path = require('path');
const mongoose = require('mongoose');
const bodyParser = require('body-parser');
const expressValidator = require('express-validator');
const flash = require('connect-flash');
const session = require('express-session');
const passport = require('passport');
const config = require('./config/database');

//, { useNewUrlParser: true }
//mongoose.connect(config.database);
mongoose.connect('mongodb://localhost:27017/nodekb');
let db = mongoose.connection;

//Check Connection 
db.once('open', () => console.log('Connected to MongoDB'))

//Check For DB errors
db.on('error', (err) => console.log(err));

//Init App
const app = express();

//Bring in Models
let Article = require('./models/article');

//Load View Engine
app.set('views', path.join(__dirname, 'views'));
app.set('view engine', 'pug');

//Body Parser Middleware
// parse application/x-www-form-urlencoded
app.use(bodyParser.urlencoded({
    extended: false
}));
// parse application/json
app.use(bodyParser.json());

//Set Public Folder
app.use(express.static(path.join(__dirname, 'public')));

//Express Session Middleware
app.use(session({
    secret: 'keyboard cat',
    resave: true,
    saveUninitialized: true
}));

//Express Messages Middleware
app.use(require('connect-flash')());
app.use(function (req, res, next) {
  res.locals.messages = require('express-messages')(req, res);
  next();
});

//Express Validator Middleware
app.use(expressValidator({
    errorFormatter: (param, msg, value) => {
        var namespace = param.split('.'),
        root = namespace.shift(),
        formParam = root;

        while (namespace.length) {
            formParam += '[' + namespace.shift() + ']';
        }
        return {
            param: formParam,
            msg: msg,
            value: value
        };
    }
}));

//Pasport Config
require('./config/passport')(passport);

//Passport MIddleware
app.use(passport.initialize());
app.use(passport.session());

//initialize global variable user
app.get('*', (req,res,next)=>{
    res.locals.user = req.user || null;
    next();
});

//Home Route
app.get('/', (req, res) => {
    Article.find({}, (err, articles) => {
        if (err) {
            console.log(err);
        } else {
            res.render('index', {
                title: 'Articles',
                articles
            });
        }
    });

});

//Route Files
let articles = require('./routes/articles');
let users = require('./routes/users');
app.use('/articles', articles);
app.use('/users', users);

//Start Server
const PORT = process.env.PORT || 4000;
app.listen(PORT, () => console.log(`Server started on port ${PORT} ...`));