My Sequelize index.js for model association / transaction

sequelize-models-index.js

'use strict'

const fs        = require('fs')
const path      = require('path')
const Sequelize = require('sequelize')
const basename  = path.basename(module.filename)
const config    = require(__dirname + '/../config')
const env       = config.NODE_ENV
const envConfig = config[env] // environment specific configs
const _         = require('lodash')
const db        = {}
const cls       = require('cls-hooked') // FIXME using cls-hooked while cls does not support async hooks

const sequelizeReadonlyPlugin = require('sequelize-noupdate-attributes')

const rimraf = require('rimraf')
const utils = require('../utils')


if (env === 'development' && envConfig.storage) {
  //rimraf.sync(envConfig.storage)
  const sqlite = require('sqlite3')
  new sqlite.Database(envConfig.storage)
}

// CLS ===========================================================================

const clsNamespace = cls.createNamespace(config.sequelize.clsNamespace)
Sequelize.useCLS(clsNamespace)

// SEQUELIZE INSTANCE ============================================================
let sequelize
if (envConfig.use_env_variable) {
  console.log('Using env variable for database.')
  const databaseURI = utils.requireEnv(envConfig.use_env_variable)
  console.log('Database URI:', databaseURI)
  sequelize = new Sequelize(databaseURI, { ...config.sequelize })
} else {
  console.log('Using database config:\n', { ...envConfig, ...config.sequelize })
  sequelize = new Sequelize({ ...envConfig, ...config.sequelize })
}

sequelizeReadonlyPlugin(sequelize)

// MODELS ========================================================================

const pascalCase = str => _.upperFirst(_.camelCase(str))

fs
  .readdirSync(__dirname)
  .filter(file => file.indexOf('.') !== 0 && file !== basename && file.slice(-3) === '.js')
  .forEach(file => {
    const model = sequelize.import(path.join(__dirname, file))
    db[pascalCase(model.name)] = model
  })

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

async function transaction(task) { // NOTE SQLITE can have only 1 active transaction
  return clsNamespace.get('transaction') ? task() : sequelize.transaction(task)
}

db.sequelize = sequelize
db.Sequelize = Sequelize
db.clsNamespace = clsNamespace
db.transaction = transaction  

// Proxy "db" to throw error on missing models
const proxiedDB = utils.proxyErrorOnMissingProperty(db)

module.exports = proxiedDB