Get the Preplance app for a seamless learning experience. Practice offline, get daily streaks, and stay ahead with real-time interview updates.
Get it on
Google Play
4.9/5 Rating on Store
Node Js · Question Set
Node Internals & Performance interview questions for placements and exams.
Questions
14
Included in this set
Subject
Node Js
Explore more sets
Difficulty
Mixed
Level of this set
Go through each question and its explanation. Use this set as a focused practice pack for Node Js.
The assert module helps test conditions in code. It throws errors if an expression evaluates to false, making it useful for debugging and creating unit tests in Node.js.
const assert = require('assert');
assert.strictEqual(2 + 2, 4);For complete preparation, combine this set with full subject-wise practice for Node Js. You can also explore other subjects and sets from the links below.
Express simplifies HTTP server creation and routing. It handles requests, middleware, and responses easily, making it ideal for APIs and full-stack apps. It’s fast, minimal, and widely supported.
The connect module provides a middleware framework for handling HTTP requests. It’s the foundation of Express. Developers can plug in middleware for cookies, sessions, authentication, and error handling.
const connect = require('connect');
const app = connect();
app.use((req,res)=>{res.end('Hello Connect');});
app.listen(3000);LTS stands for Long-Term Support. These Node.js versions receive stability, security, and bug fixes for about 30 months, making them suitable for production environments.
ESLint is a static code analysis tool that identifies syntax issues, enforces coding standards, and improves code quality. It helps keep a consistent style and catches bugs early.
Node.js runs JavaScript on a single thread but can create child processes using `child_process` or worker threads. These allow parallel execution without blocking the event loop.
const { Worker } = require('worker_threads');
new Worker('./task.js');A thread pool is a collection of background threads used for heavy I/O operations like file access and compression. Node.js uses the libuv library to manage this pool and distribute tasks efficiently.
Clusters create multiple Node.js processes, each running on a CPU core. Worker threads, however, share memory within a single process. Workers are better for CPU-intensive tasks; clusters are ideal for scaling web servers.
You can use console.time/console.timeEnd or performance.now() to measure how long async operations take. These tools help track performance bottlenecks in APIs or I/O-heavy code.
console.time('fetch');
await fetch('https://api.com');
console.timeEnd('fetch');Tracing collects information about function calls and system events to analyze performance. Node.js’s built-in tracing API and tools like Chrome DevTools help identify bottlenecks and optimize runtime behavior.
The crypto module enables secure data encryption, hashing, and signing. It supports algorithms like AES, RSA, and SHA, helping developers secure passwords, tokens, and sensitive data.
const crypto=require('crypto');
const hash=crypto.createHash('sha256').update('secret').digest('hex');
console.log(hash);Libuv is the C library that powers Node.js’s event loop and asynchronous I/O operations. It handles non-blocking file I/O, DNS, and network operations across different operating systems, enabling Node to stay single-threaded yet highly concurrent.
Global objects are accessible anywhere in Node.js without importing them. Examples include `process`, `console`, `Buffer`, `__dirname`, and `setTimeout`. These objects provide environment info, logging, and system-level access.
Clustering lets Node.js utilize multiple CPU cores. It spawns multiple worker processes sharing the same server port. This improves throughput and handles higher concurrent loads efficiently.
const cluster=require('cluster');
const http=require('http');
if(cluster.isPrimary){for(let i=0;i<4;i++)cluster.fork();}
else{http.createServer((req,res)=>res.end('Hello')).listen(3000);}