A mongoose connection helper script that builds a connection string from environment variables

dbhelper.js

// env.test file:
// DB_HOST="localhost"
// DB_PORT="27017"
// DB_NAME="dbname"
// DB_USER="dbusername"
// DB_PASS="dbpassword"

require('custom-env').env(true)
const mongoose = require('mongoose')

exports.connect = async () => {
    try {
        let connectionString = await this.connectionString()

        mongoose.connection.on('error', (err) => {
            throw new Error(`Unable to connect to db: ${err.message}`)
        })

        return await mongoose.connect(connectionString, { useNewUrlParser: true, useFindAndModify: false })
    } catch (err) {
        throw new Error(`dbhelper.connect: ${err.message}`)
    }
}

exports.connectionString = () => {
    let connectionString = ''
    try {
        if (process.env.DB_PROTOCOL) {
            connectionString += `${process.env.DB_PROTOCOL}://`
        } else {
            connectionString += `mongodb://`
        }
        if (process.env.DB_USER && process.env.DB_PASS) {
            connectionString += `${process.env.DB_USER}:${process.env.DB_PASS}@`
        }
        connectionString += `${process.env.DB_HOST}:${process.env.DB_PORT}/${process.env.DB_NAME}`
    } catch (err) {
        throw new Error(`dbhelper.connectionString: ${err.message}`)
    }
    return connectionString
}

const {ConnectionString} = require('connection-string');

const cs = new ConnectionString();

cs.setDefaults({
    protocol: process.env.DB_PROTOCOL || 'mongodb',
    user: process.env.DB_USER,
    password: process.env.DB_PASS,
    hosts: [
        {name: process.env.DB_HOST, port: process.env.DB_PORT}
    ],
    path: [process.env.DB_NAME]
});

// to generate the connection string:
const connection = cs.toString();