How to retrieve data from mongodb - node.js

Question

I am unable to retrieve data from mongodb.
Problem is: the code Article.find({}); is not working to retrieve data from database.
I am using WebStorm IDE. I want to retrieve all the data from data base.
Please help me to find the error in my code.
database.js
module.exports = {
database:'mongodb://localhost:27017/shopping_site',
}
models/article.js
let mongoose = require('mongoose');
// Article Schema
let articleSchema = mongoose.Schema({
title:{
type: String,
required: true
},
author:{
type: String,
required: true
},
body:{
type: String,
required: true
}
});
let Article = module.exports = mongoose.model('Article', articleSchema);
index.pug
extends layout
block content
h1 #{title}
ul.list-group
each article, i in articles
li.list-group-item= article.title
app.js
var createError = require('http-errors');
var express = require('express');
var path = require('path');
var cookieParser = require('cookie-parser');
var logger = require('morgan');
var mongoose = require('mongoose');
var config = require('./config/database');
var bodyParser = require('body-parser');
var app = express();
// Bring in Models
let Article = require('./models/article');
//database connectionkjvhgc
mongoose.connect(config.database);
let db = mongoose.connection;
// Check connection
db.once('open', function(){
console.log('Connected to MongoDB');
});
// Check for DB errors
db.on('error', function(err){
console.log(err);
});
// view engine setup
app.set('views', path.join(__dirname, 'views'));
app.set('view engine', 'pug');
app.use(logger('dev'));
app.use(express.json());
app.use(express.urlencoded({ extended: false }));
app.use(cookieParser());
app.use(express.static(path.join(__dirname, 'public')));
// Home Route
app.get('/', function(req, res){
Article.find({}, function(err, articles){
if(err){
console.log(err);
} else {
res.render('index', {
title:'Articles',
articles: articles
});
}
});
});
//set routes
// catch 404 and forward to error handler
app.use(function(req, res, next) {
next(createError(404));
});
//body-parser
// parse application/x-www-form-urlencoded
app.use(bodyParser.urlencoded({ extended: false }))
// parse application/json
app.use(bodyParser.json())
// error handler
app.use(function(err, req, res, next) {
// set locals, only providing error in development
res.locals.message = err.message;
res.locals.error = req.app.get('env') === 'development' ? err : {};
// render the error page
res.status(err.status || 500);
res.render('error');
});
module.exports = app;

Answer 1

move database connection code into db.js and import same in article.js
db.js
let uristring = <your connection string or import database.js>;
mongoose.connect(uristring);
// When successfully connected
mongoose.connection.on('connected', function() {
console.log('Mongoose connection open to cluster');
});
// If the connection throws an error
mongoose.connection.on('error', function(err) {
console.log('Mongoose connection error: ' + err);
});
// When the connection is disconnected
mongoose.connection.on('disconnected', function() {
console.log('Mongoose connection disconnected');
});
// When the connection is open
mongoose.connection.on('open', function() {
console.log('Mongoose connection is open');
});
module.exports = mongoose;
then in article.js
const mongoose = require('mongoose');
require('../db');

Answer 2

First lets bring in your model,
require('./models/article');
the create a variable for the model
const Article = mongoose.model('Article');
Next to display your articles from db
app.get('/', (req, res) => {
Article.find({}).then(Article => {
res.render('index', {Article:Article});
}).catch(err => console.log(err));
});
I hope this helps