Snippets from Real Javascript Interviews

These JavaScript snippets are inspired by real interview questions and actual tasks from my job. They’re crafted to give you hands-on experience with advanced JavaScript concepts that companies truly care about.

I’m a frontend developer who went through 20+ interviews — and I compiled everything companies were asking. Each snippet is derived from real-world scenarios. If you’re familiar with all these topics, you can thrive at any company, on any project — and feel confident doing it.

✅ Pro tip: Copy any snippet, run it, and step through it with a debugger to truly understand what’s going on under the hood.

🔍 Do you know the output (not guess)?

What will this print?

const promise1 = Promise.resolve();
const promise2 = Promise.resolve();
 
promise1.then(() => console.log(1)).then(() => console.log(2));
promise2.then(() => console.log(3)).then(() => console.log(4));

And how about this?

console.log("1");
 
setTimeout(function () {
  console.log("2");
 
  Promise.resolve().then(function () {
    console.log("3");
  });
}, 0);
 
Promise.resolve().then(function () {
  console.log("4");
 
  setTimeout(function () {
    console.log("5");
  }, 0);
});
 
requestAnimationFrame(function () {
  console.log("7");
});
 
console.log("6");

Understand the Event Loop

🔥 Pass your next interview — let’s dive in 👇