Local MongoDB server not starting - node.js

Question

I am starting to learn NodeJS and Express framework. I was following a tutorial where I had a basic application
const express = require('express');
const exphbs = require('express-handlebars');
const mongoose = require('mongoose');
const app = express();
mongoose.Promise = global.Promise
// mongoose
mongoose.connect('mongodb://localhost/vidjot-dev')
.then(() => console.log("Mongo DB started"))
.catch(err => console.error(err));
// handlebars middleware
app.engine('handlebars', exphbs({
defaultLayout: 'main'
}));
app.set('view engine','handlebars')
// index route
app.get('/', (req, res) =>{
const title = "Welcome"
res.render('index',{
title : title
});
});
app.get('/about', (req,res) =>{
res.render('about');
});
const port = 5000;
app.listen(port, () => {
console.log(`Server started on port ${port}`);
});
I tried to start the node js server from the console using the command
nodemon app
Where app is the name of the JS file app.js
When I tried to start the server, I got this error
{ MongoNetworkError: failed to connect to server [localhost:27017] on first connect [MongoNetworkError: connect ECONNREFUSED 127.0.0.1:27017]
at Pool.<anonymous> (/Users/sriramr/Desktop/node/vidjot/node_modules/mongodb-core/lib/topologies/server.js:503:11)
at emitOne (events.js:116:13)
at Pool.emit (events.js:211:7)
at Connection.<anonymous> (/Users/sriramr/Desktop/node/vidjot/node_modules/mongodb-core/lib/connection/pool.js:326:12)
at Object.onceWrapper (events.js:317:30)
at emitTwo (events.js:126:13)
at Connection.emit (events.js:214:7)
at Socket.<anonymous> (/Users/sriramr/Desktop/node/vidjot/node_modules/mongodb-core/lib/connection/connection.js:245:50)
at Object.onceWrapper (events.js:315:30)
at emitOne (events.js:116:13)
at Socket.emit (events.js:211:7)
at emitErrorNT (internal/streams/destroy.js:64:8)
at _combinedTickCallback (internal/process/next_tick.js:138:11)
at process._tickCallback (internal/process/next_tick.js:180:9)
name: 'MongoNetworkError',
message: 'failed to connect to server [localhost:27017] on first connect [MongoNetworkError: connect ECONNREFUSED 127.0.0.1:27017]' }
I tried setting the DB path again but it wasn't of any use. I tried to start mongod from the terminal but got the same error again. How do I fix this?
EDIT:
I have the directories data/db created and I just ran
mongod --dbpath <DIRECTORY>
and got this error
2018-02-16T17:42:02.657+0530 I CONTROL [initandlisten] MongoDB starting : pid=76227 port=27017 dbpath=/Users/sriramr/mongodb/data/db 64-bit host=MACBOOKs-MacBook-Air.local
2018-02-16T17:42:02.657+0530 I CONTROL [initandlisten] db version v3.6.2
2018-02-16T17:42:02.657+0530 I CONTROL [initandlisten] git version: 489d177dbd0f0420a8ca04d39fd78d0a2c539420
2018-02-16T17:42:02.657+0530 I CONTROL [initandlisten] OpenSSL version: OpenSSL 0.9.8zh 14 Jan 2016
2018-02-16T17:42:02.657+0530 I CONTROL [initandlisten] allocator: system
2018-02-16T17:42:02.657+0530 I CONTROL [initandlisten] modules: none
2018-02-16T17:42:02.657+0530 I CONTROL [initandlisten] build environment:
2018-02-16T17:42:02.657+0530 I CONTROL [initandlisten] distarch: x86_64
2018-02-16T17:42:02.657+0530 I CONTROL [initandlisten] target_arch: x86_64
2018-02-16T17:42:02.657+0530 I CONTROL [initandlisten] options: { storage: { dbPath: "/Users/sriramr/mongodb/data/db" } }
2018-02-16T17:42:02.659+0530 I - [initandlisten] Detected data files in /Users/sriramr/mongodb/data/db created by the 'wiredTiger' storage engine, so setting the active storage engine to 'wiredTiger'.
2018-02-16T17:42:02.660+0530 I STORAGE [initandlisten] exception in initAndListen: InvalidOptions: Requested option conflicts with current storage engine option for directoryPerDB; you requested false but the current server storage is already set to true and cannot be changed, terminating
2018-02-16T17:42:02.661+0530 I NETWORK [initandlisten] shutdown: going to close listening sockets...
2018-02-16T17:42:02.661+0530 I NETWORK [initandlisten] removing socket file: /tmp/mongodb-27017.sock
2018-02-16T17:42:02.661+0530 I CONTROL [initandlisten] now exiting
2018-02-16T17:42:02.661+0530 I CONTROL [initandlisten] shutting down with code:100

Answer 1

Open terminal/CMD and start your MongoDB server using command mongod
This command will start MongoDB for you and so your app can connect to it on localhost:27017

Answer 2

Are you sure you are running mongo? Your URL points to localhost, which means you need to be serving it (Separate from serving your app with nodemon).
This link shows how to run mongo from shell