db.js

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

const sequelize = new Sequelize(
    process.env.DB_NAME || config.development.database,
    process.env.DB_USER || config.development.username,
    process.env.DB_PASSWORD || config.development.password,
    {
        host: process.env.DB_HOST || config.development.host,
        port: process.env.DB_PORT || config.development.port || '3306',
        dialect: process.env.DB_DIALECT || config.development.dialect,
        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 connected');
    return db;
});