mongodb.js

import mongoose from 'mongoose';
import grid from 'gridfs-stream';
import config from 'config';
import url from 'url';

const  mongodb = config.get('mongodb');
const { Schema } = mongoose;

grid.mongo = mongoose.mongo;

const mongodbUri = url.format({
  slashes: true,
  protocol: mongodb.protocol,
  hostname: mongodb.host,
  port: mongodb.port
});

export default (() => {

  const connectDb = (uri, useGridFS=false) => {

    let db = mongoose.createConnection(mongodbUri);

    db.on('error', console.error.bind(console, 'connection error'));
    db.once('open', () => {
      console.log(`Connection with database \'${uri}\' succeeded.`);
    });

    if (!useGridFS) {
      return db;
    } else {
      return grid(db.db);
    }
  };

  return Object.freeze({
    connectDb,
    Schema
  });

})();