Node.js Study Guide 2026
Everything you need to pass the Node.js exam in one place: the exam format, every topic to study, real practice questions with explanations, flashcards, and full-length practice tests. Free, no sign-up needed.
📋 Node.js Exam Format at a Glance
📚 Node.js Topics to Study (55)
✍️ Sample Node.js Questions & Answers
1. What risk does setting --max-old-space-size too low in production introduce?
An undersized heap causes the V8 garbage collector to fail to reclaim enough memory, triggering fatal OOM process exits under typical traffic.
2. Which pattern allows you to avoid uncaught errors when using `async` functions as Express route handlers?
Express does not catch async errors automatically, so you must wrap with try/catch and pass errors to `next(err)` to trigger error-handling middleware.
3. What does `sinon.stub()` return when called without a replacement implementation?
A Sinon stub without a configured behavior returns `undefined` and records all calls, arguments, and call counts.
4. When there is no more data to read, the stream sends an end event.
Explanation: When there is no more data to read, a stream fires an end event.
5. How do you install a specific version of a package, e.g., lodash version 4.17.15?
Appending `@version` to the package name tells npm to install that exact version.
6. What is the professional standard for committing secrets like database passwords into a Git repository?
Secrets in Git history can be exposed even if later deleted, and private repos can become public or be cloned.