App.js

import Express from 'express';
import http from 'http';

import Response from './Response';

export default class App {
    constructor (services) {
        this.services = services;
    }

    start () {
        const { express, db } = this.services;

        express.set('services', this.services);

        // configure top-level express middleware, e.g. bodyParser, cors etc

        express.use(async (request, response, next) => {
            const {
                session, events,
            } = this.services;

            events.emit('boot', this.services);

            // boot any services, e.g. establish database connection, 
            // read request headers to initialize the session etc.

            events.emit('ready', this.services);
            
            // not in the scope of this example,
            // but there is a similar event emitted from the 
            // last express middleware we use to wrap our route response
            // into an API response
            events.emit('request', request);

            next();
        });

        // register express routes 
        // register error/response handling middleware

        process.on('unhandledRejection', (err) => {
            const { logger } = this.services;

            logger.error(err);
        });

        return express;
    }

    serve () {
        const {
            express,
            config,
            logger,
        } = this.services;

        const port = config.port || 3000;
        const hostname = config.hostname || 'localhost';

        express.set('port', port);
        express.set('hostname', hostname);

        const server = http.createServer(express);

        server.listen({
            port,
            host: hostname,
        });

        server.on('error', (err) => {
            // handle your errors  
        });

        return this;
    }
}

index.js

import App from './App';
import services from './services';

const app = new App(services());

app.start();

export default app;

serve.js

#!/usr/bin/env node
import app from './app';

app.serve();

test-app-factory.js

// And here is the sample app factory, we can use for our tests
import Seeder from './seeder';
import Sequelize from 'sequelize';
import nodemailer from 'nodemailer';
import Services from '../../src/services';
import App from '../../src/app/App';

export default async function () {
    const services = Services();

    const connection = new Sequelize('', '', '', {
        dialect: 'sqlite',
        logging: false,
        operatorsAliases: false,
        define: {
            underscored: true,
        },
    });

    const transport = nodemailer.createTransport({
        jsonTransport: true,
    });

    services.register('dbConnection', connection);
    services.register('seeder', Seeder, ['db']);
    services.register('mailerTransport', transport);
    services.register('stripe', {});

    services.db.loadModels(services);

    await services.db.sync({
        force: true,
    });

    return new App(services).start();
}