MongoDB Connection

mg-config.js

const mgConfig = {
    mgHost: 'localhost',
    mgPort: 27017,
    mgDb:   ''
};

const mgLocalConfig = `mongodb://${mgConfig.mgHost}:${mgConfig.mgPort}/${mgConfig.mgDb}`;

export default mgLocalConfig;

mongodb-connector.js

import { MongoClient } from 'mongodb';
import promisify from 'es6-promisify';
import colors from 'colors';

import mgLocalConfig from './mg-config.js';

let _connection;

const connect = () => {
    return promisify(MongoClient.connect)(process.env.MONGO_CONNECTION_STRING || mgLocalConfig);
};

/**
 * Returns a promise of a `db` object. Subsequent calls to this function returns
 * the **same** promise, so it can be called any number of times without setting
 * up a new connection every time.
 */
const mgConn = () => {
    if (!_connection) {
        console.log(`[+] Enabling MongoDB client ...`.green);
        _connection = connect();
    }

    return _connection;
};

export default mgConn;

/**
 * Returns a ready-to-use `collection` object from MongoDB.
 *
 * Usage:
 *
 *   (await mongoCollection('users')).find().toArray().then( ... )
 */
export async function mgCollection(collectionName) {
    const db = await mgConn();
    return db.collection(collectionName);
}