Installing mongoose is as easy as running the npm command

npm install mongoose --save

But make sure you have also installed MongoDB for your OS or Have access to a MongoDB database.

---

Connecting to MongoDB database:

1. Import mongoose into the app:

import mongoose from 'mongoose';

2. Specify a Promise library:

mongoose.Promise = global.Promise;

3. Connect to MongoDB:

mongoose.connect('mongodb://127.0.0.1:27017/database');

/* Mongoose connection format looks something like this */
mongoose.connect('mongodb://USERNAME:PASSWORD@HOST::PORT/DATABASE_NAME');

Note:

• By default mongoose connects to MongoDB at port 27017, Which is the default port used by MongoDB.

• To connect to MongoDB hosted somewhere else, use the second syntax. Enter MongoDB username, password, host, port and database name.

MongoDB port is 27017 by default; use your app name as the db name.

Mongoose connect has 3 parameters, uri, options, and the callback function. To use them see sample below.

var mongoose = require('mongoose');

var uri = 'mongodb://localhost:27017/DBNAME';

var options = {
    user: 'user1',
    pass: 'pass'
}

mongoose.connect(uri, options, function(err){
    if (err) throw err;
    // if no error == connected
});