db.js

const config = require('./config/config.json');
const { Sequelize, DataTypes } = require('sequelize');

const sequelize = new Sequelize(
    process.env.MYSQL_DATABASE || config.development.database,
    process.env.MYSQL_USER || config.development.username,
    process.env.MYSQL_PASSWORD || config.development.password,
    {
        host: process.env.MYSQL_HOST || config.development.host,
        port: process.env.MYSQL_PORT || config.development.port || 3306,
        dialect: 'mysql',
        operatorAliases: false,
        pool: {
            max: 5,  //maximum number of connection in pool
            min: 0,  //minimum number of connection in pool
            acquire: 30000, //maximum time, in milliseconds, that a connection can be idle before being released
            idle: 10000 // maximum time, in milliseconds, that pool will try to get connection before throwing error
        },
    }
);

module.exports = sequelize.authenticate()
    .then((db) => {
        console.log('MYSQL conectado correctamente a la base de datos');
        return db;
    });