https://readosapien.com/queues-in-node-js/- queues in node js

start.js

console.log("1");
setTimeout(() => console.log("2"),0);
var promise = new Promise(function(resolve, reject) {
  resolve();
});
promise.then(function(resolve) {
  console.log('3');
})
.then(function(resolve) {
  console.log('4');
});
console.log("5");