server.js

/**
 * @file Manages the run configuration for the whole application, defines the port used,
 * creates the http server and defines some listeners for the server.
 * @author Gabriel <gabrielsonchia@gmail.com> <20/06/2020 06:37am>
 * @since 0.1.0
 * Last Modified: Gabriel <gabrielsonchia@gmail.com> <13/07/2020 06:17pm>
 */

const http = require('http');
const dotenv = require('dotenv');
// load env configuration as early as possible
dotenv.config();
const config = require('./src/config');
const app = require('./app')(config);
// eslint-disable-next-line import/order
const debug = require('debug')(`${config.applicationName}:server`);


/**
 * Get port from environment and store in Express.
 */
const port = normalizePort(process.env.PORT || config.port);
app.set('port', port);

/**
 * Create HTTP server.
 */
const server = http.createServer(app);

/**
 * Listen on provided port, on all network interfaces.
 */

server.listen(port);
server.on('error', onError);
server.on('listening', onListening);

/**
 * Normalize a port into a number, string, or false.
 */

function normalizePort(val) {
  const parsedPort = parseInt(val, 10);

  if (isNaN(parsedPort)) {
    // named pipe
    return val;
  }

  if (parsedPort >= 0) {
    // port number
    return parsedPort;
  }

  return false;
}

/**
 * Event listener for HTTP server "error" event.
 */

function onError(error) {
  if (error.syscall !== 'listen') {
    throw error;
  }

  const bind = typeof port === 'string' ? `Pipe ${port}` : `Port ${port}`;

  // handle specific listen errors with friendly messages
  switch (error.code) {
    case 'EACCES':
      config.logger.error(`${bind} requires elevated privileges`);
      process.exit(1);
      break;
    case 'EADDRINUSE':
      config.logger.error(`${bind} is already in use`);
      process.exit(1);
      break;
    default:
      throw error;
  }
}

/**
 * Event listener for HTTP server "listening" event.
 */

function onListening() {
  const addr = server.address();
  const bind = typeof addr === 'string' ? `pipe ${addr}` : `port ${addr.port}`;
  debug(`Listening on ${bind}`);
}