connection.js

require('dotenv').config();

const environment = process.env.NODE_ENV || 'development';

const config = (environment) => {
  if (environment === 'development') {
    return {
      client: 'mysql',
      connection: {
        host     : process.env.DB_HOST,
        user     : process.env.DB_USER,
        password : process.env.DB_PASS,
        database : process.env.DB_NAME,
        port     : process.env.DB_PORT,
        charset  : 'utf8'
      },
      pool: {
        min: 0,
        max: 20,
      },
    }
  } else {
    // change accordingly
    return {
      client: 'mysql',
      connection: {
        host     : process.env.DB_HOST,
        user     : process.env.DB_USER,
        password : process.env.DB_PASS,
        database : process.env.DB_NAME,
        port     : process.env.DB_PORT,
      },
      pool: {
        min: 2,
        max: 10
      },
      migrations: {
        tableName: 'knex_migrations'
      }
    }
  }
}

const connection = require('knex')(config(environment));

module.exports = connection;