// Learning JavaScript
// chapter 14 : Asynchronous Programming

// makes Promise

function countdown(seconds) {
    return new Promise(function(resolve, reject) {
        for (let i = seconds; i >= 0; i--) {
            setTimeout(function() {
                if (i > 0) console.log(i + '...');
                else resolve(console.log('GO!'));
            }, (seconds - i) * 1000);
        }
    });
}