Mongoose index models connections like Sequelize Raw

index.js

const fs = require('fs')
const path = require('path')
const mongoose = require('mongoose')

const basename = path.basename(module.filename)
const db = {}

mongoose.connect(process.env.MONGODB_URI)

fs
  .readdirSync(__dirname)
  .filter(file =>
    (file.indexOf('.') !== 0) &&
    (file !== basename) &&
    (file.slice(-3) === '.js'))
  .forEach((filename) => {
    const filepath = path.join(__dirname, filename)

    const imported = (require(filepath).default) ?
      require(filepath).default : require(filepath)

    if (typeof imported.modelName !== 'undefined') {
      db[imported.modelName] = imported
    }
  })

Object.keys(db).forEach((modelName) => {
  if (db[modelName].associate) {
    db[modelName].associate(db)
  }
})

module.exports = db