Promises are blocking
Promises are just a notification mechanism and does not relate to non-blocking
JavaScript
var prom = new Promise(resolve => {
setTimeout(function() {
console.log('hello');
resolve('yo')
}, 3000)
});
prom.then(res => console.log(res));
for (let i = 0; i < 1000000; i++) {
for (let j = 0; j < 100000; j++) {
}
}
console.log('hi');