How to use the Node.js MCQ Quiz
- 1. Choose the length10 random Node.js questions, or all 25.
- 2. AnswerTap an option. You see straight away whether it's right, with a one-line reason.
- 3. ReviewFinish to get your score and a list of every question with the correct answer.
Topics in the quiz
- Event loop: non-blocking I/O, and the order of
process.nextTick, Promise callbacks andsetTimeout. - Modules: require and module.exports, and how to switch on ES modules.
- npm: package.json, what ^ allows, package-lock.json and devDependencies.
- Core modules: http, fs (sync vs async), path, streams and EventEmitter.
- Express: middleware, express.json(), req.params vs req.query, status codes and error handlers.
- Performance and async: clustering, worker threads, async/await and unhandled rejections.
- Good practice: keeping secrets in environment variables.
A sample question explained
Which runs first after the current code: a resolved Promise's .then() or setTimeout(fn, 0)? The Promise callback wins. It is a microtask, and Node empties the microtask queue before moving on to the timers phase of the event loop. process.nextTick callbacks run even earlier, before other microtasks. A delay of 0 ms doesn't mean "now"; it means "at the next timers phase".
Getting this order right explains many real bugs, such as a log line appearing later than expected or a loop of nextTick calls starving I/O. You can watch the order happen step by step in the JavaScript event loop visualizer. Each attempt shuffles the 25 questions, and the result screen lists every question with the right answer.
Frequently asked questions
Do I need to know Express for this quiz?
Five questions are about Express basics; the rest are core Node.js.
Which Node.js version is assumed?
Current LTS versions (20 and 22). Behaviour like unhandled rejections crashing the process applies from Node 15 on.
Are the questions from real tests?
No. Uncodemy wrote them to cover common back-end interview topics.
Is the Node.js MCQ quiz free to take?
Yes. The Node.js MCQ quiz lets you answer every question with no form. At your first score screen we ask for your name and WhatsApp number once; after that, the Node.js MCQ quiz and all other Uncodemy tools stay open.