**Asynchronous and Event-Driven:** Node.js uses non-blocking, event-driven architecture, making it lightweight and efficient for real-time applications. **Single-Threaded with Event Loop:** It operates on a single-threaded model with event looping, enabling it to handle multiple connections simultaneously without creating new threads. **NPM (Node Package Manager):** Node.js comes with npm, the largest ecosystem of open-source libraries and tools, making it easy to integrate third-party modules. **Cross-Platform:** It can run on various platforms like Windows, macOS, and Linux. **Scalable:** Ideal for building scalable network applications due to its non-blocking I/O model.

What is nodejs?

Difficulty: 3/10

event loop, non-blocking I/O, runtime environment

Node.js is an open-source, cross-platform runtime environment that allows developers to execute JavaScript code outside of a web browser. It is built on Chrome's V8 JavaScript engine, which compiles JavaScript directly to native machine code for high performance.It implements an event‑driven, non‑blocking I/O model, single threaded event loop and uses libuv for handling of async operations.

Key Features of Node.js:

1
Asynchronous and Event-Driven: Node.js uses non-blocking, event-driven architecture, making it lightweight and efficient for real-time applications.
2
Single-Threaded with Event Loop: It operates on a single-threaded model with event looping, enabling it to handle multiple connections simultaneously without creating new threads.
3
NPM (Node Package Manager): Node.js comes with npm, the largest ecosystem of open-source libraries and tools, making it easy to integrate third-party modules.
4

Scenario Questions

0-2 years experience

2-5 years experience

1We added a new third‑party library that uses many callbacks, and the request latency spiked. How would you investigate whether Node's event loop is the bottleneck?

What is nodejs?

Scenario Questions

Follow-up Questions