Questions
7 of 10
1What is nodejs?
2Why is Node.js Single-threaded?
3If Node.js is single-threaded, then how does it handle concurrency?
4What is the package.json file?
5How to install delete and update a dependency in node js?
6What are some of the most commonly used libraries in Node.js?
7What are the pros and cons of Node.js?
8What is libuv?
9Why does Node.js use the V8 engine?
10V8 engine, event loop and libuv. What is the role of these three components? Where do they fit in the NodeJS environment and what role does each play?
nodejsnodejs
Basics
Event Loop
Buffers
Streams
Events
Time functions
Clusters
Crypto
Modules
Worker Threads
File Operations
Threads
Performance Optimisation
Websockets
07 / 10

What are the pros and cons of Node.js?

Pros
  1. 1

    It uses JavaScript, which is well-known amongst developers

  2. 2

    Fast I/O due to an event-based model

  3. 3

    Best suited for streaming huge amounts of data

  4. 4

    NPM has over 50,000 packages making it easy to implement complex features

Cons
  1. 1

    Since Node.js is single-threaded, It is not suitable for heavy computational tasks

  2. 2

    Using callback is complex since you end up with several nested callbacks

Difficulty: 5/10
Topics: event loop, single-threaded model, npm ecosystem

Scenario Questions

0-2 years experience
  1. 1

    How would you decide whether to use Node.js for a simple REST API that returns JSON data?

  2. 2

    What happens if you write a CPU‑intensive loop in a Node.js request handler?

  3. 3

    If you need to read a file and then send its contents over HTTP, how would you take advantage of Node's strengths?

2-5 years experience
  1. 1

    We have a microservice written in Node.js that started experiencing high latency under load. Walk me through how you'd investigate whether the event loop is the bottleneck.

  2. 2

    When integrating a third‑party library that uses native bindings, what trade‑offs do you consider about staying in the Node ecosystem?

  3. 3

    Explain why a recent deployment caused memory leaks in a Node.js service and how you would fix it.

5-8 years experience
  1. 1

    Design a high‑throughput real‑time chat system using Node.js. What architectural decisions would you make to mitigate the single‑threaded limitation?

  2. 2

    If you need to run CPU‑heavy image processing alongside a Node.js web server, how would you structure the system to preserve responsiveness?

  3. 3

    Discuss the pros and cons of using Node.js versus a compiled language for a latency‑sensitive trading platform.

8+ years experience
  1. 1

    Your company is planning to migrate a legacy monolith written in Java to a microservice architecture, and you’re evaluating Node.js for many services. What long‑term maintenance and cross‑team considerations would influence that decision?

  2. 2

    When standardizing a shared library across multiple teams, how would you address the risk of divergent Node.js versions and ecosystem churn?

  3. 3

    If you need to guarantee backward compatibility for an internal API over several years, how does Node's rapid release cycle affect your strategy?

Follow-up Questions

  • ❓Can you give an example where the event loop became a bottleneck?
  • ❓How would you mitigate callback hell in a large codebase?
  • ❓What signals would make you choose a different runtime?