event-loop-phases.js

const fs = require("fs");

setImmediate(() => console.log(1)); // 8
Promise.resolve().then(() => console.log(2)); // 3
process.nextTick(() => console.log(3)); // 2
fs.readFile(__filename, () => {
  console.log(4); // 1
  setTimeout(() => console.log(5)); // 4
  setImmediate(() => console.log(6)); // 7
  process.nextTick(() => console.log(7)); // 6
});
console.log(8); // 5