initServer.js

const { readFileSync } = require('fs');

const initServer = async (config, app) => {
  const logger = config.logger.createLogger('initServer');

  try {
    const serverObject = {};

    if (config.app.server.protocol == 'https') {
      //https server
      const https = require('https');

      // loading SSL certificates
      serverObject.server = https.createServer({
        key: readFileSync('config/ssl/private.key'),
        cert: readFileSync('config/ssl/certificate.crt'),
        ca: readFileSync('config/ssl/ca_bundle.crt')
      }, app);

    } else {
      //http server init
      const http = require('http');
      serverObject.server = http.createServer(app);
    }

    if (config.app.server.socket) {
      //init socket io
      const socket = require('socket.io');

      if (config.app.server.socket.port) {
        //if port is present then init socket on that port
        serverObject.io = socket(config.app.server.socket.port);
      } else {
        // else use the provieded server to init the socket
        serverObject.io = socket(serverObject.server);
      }
    }

    if (config.app.db) {
      //mongo db initiaization.
      const mongoose = require('mongoose');
      mongoose.Promise = Promise;

      //if authentication available, then use the following.
      const auth = config.app.db.username && config.app.db.password ? {
        user: config.app.db.username,
        pass: config.app.db.password,
        auth: {
          authDB: 'admin'
        }
      } : {};

      //connecting to mongoose.
      await mongoose.connect(`mongodb://${config.app.db.host}/${config.app.db.database}`, {
        ...auth,
        useNewUrlParser: true
      });
    }

    return serverObject;

  } catch (error) {
    logger.error(error);
  }
};

module.exports = initServer;