Engineering, Design, Marketing, and More

Node.js interview questions

The most popular questions

Use our complementary questions and answers to filter and hire the best. Questions crowdsourced by our clients, answers by Punch. We provide these complementary questions to help our clients more quickly create tests for potential hires at their organizations.

Get a question answered
Punch offers four divisions of services: design, engineering, staffing, and demand

Interview questions for your next interview

Question
Does Node.js provide built-in support for debugging?
Answer
Node7 introduced this new feature. It includes an out-of-process debugging utility accessible via a TCP-based protocol and built-in debugging client. To use it, start Node.js with the debug argument followed by the path to the script to debug. For example$ node debug YouAwesomeScript.jsThis command will show you a prompt indicating successful launch of debugger.
Question
Why Node.js does not require multi threading to support parallel processing?
Answer
Node.js is single threaded and uses event loop to manage the processes. The asynchronous nature of Node.js results in non blocking handling of I/O, network or similar calls. These calls are usually blocking in other languages and require special threading to effectively make them work in parallel.

Find developers today

Hire a Punch engineer

Punch offers four divisions of services: design, engineering, staffing, and demand. Our four divisions form the core of our People Forward Approach.

Contact us
Find developers today
Question
What is the difference between child_process.fork() and cluster.fork()?
Answer
Cluster allows TCP servers to be shared between workers whereas Child Process does not. Cluster.fork is implemented on top of child_process.fork. And in general you can say that Cluster wraps the functionality of Child_Process in a more useful way. Both are Node.js modules.
Question
What is the difference between url.host and url.hostname?
Answer
Both methods get and set the hostname section of url. Url.hostname does not include the port. E.gconst myURL = new URL('https://sadiq.org:8080/hassaan');
console.log(myUrl.hostname) // sadig.org
console.log(myUrl.host) //sadiq.org:8080
Question
Since Node.js runs on a single thread, how can a user take advantage of multi-core systems?
Answer
A single instance of Node.js runs in a single thread. To take advantage of multi-core systems, you can launch a cluster of Node.js processes to handle the load. The cluster module can create child processes which share server ports. You can import cluster like this. const cluster = require('cluster');Cluster have several useful methods like fork(), exit(), message(), isMaster(), isWorker() etc.
Question
What is the difference between Buffer.alloc(size, fill) and Buffer.allocUnsafe(size).fill(fill)?
Answer
Buffer.alloc(size, fill) will never use the internal Buffer pool, while Buffer.allocUnsafe(size).fill(fill) will use the internal Buffer pool if size is less than or equal to half Buffer.poolSize. The difference is subtle but can be important when an application requires the additional performance that Buffer.allocUnsafe()provides.
Question
Can we manage cryptography in Node.js without using external libraries?
Answer
To use the full grown cryptography in Node.js, you don’t need to use external libraries. You can use the crypto module of Node.js. It provides cipher, decipher, Diffie-Hellman key exchanges, Elliptic Curve Diffie-Hellman (ECDH) key exchanges and similar other methods to effectively manage cryptography. Also you can generate signatures using the Sign class of this module.

Ask a question

Ask a question, and one of our engineers will answer it.

We keep our questions nice and simple to be useful for everyone, and we may not answer or publish every question.

Your number is stored privately and never shared.
By submitting a question, you agree to our terms.
Request sent. Thank you!
Send another one