---
title: "Ujjwal Kar (@ujjwalkar21) | Hashnode"
description: "Versatile Software Engineer specializing in Full Stack Development with a proficiency in executing Data Science projects."
url: "https://hashnode.com/@ujjwalkar21"
---

@ujjwalkar21

# Ujjwal Kar

@ujjwalkar21 · Kolkata, India · Joined November 2023

Versatile Software Engineer specializing in Full Stack Development with a proficiency in executing Data Science projects.

[Website](https://ujjwalkar.netlify.app/)

### [Bias vs Variance — Machine Learning Interview Questions](https://ujjwalkar.hashnode.dev/bias-vs-variance-machine-learning-interview-questions?utm_source=hashnode&utm_medium=feed)

Clear explanation of bias vs variance, trade-off intuition, examples, and common interview questions to help you prepare for machine learning interviews.

2 min read · [ujjwalkar.hashnode.dev](https://ujjwalkar.hashnode.dev/bias-vs-variance-machine-learning-interview-questions?utm_source=hashnode&utm_medium=feed)

[Apr 25](https://hashnode.com/posts/bias-vs-variance-machine-learning-interview-questions/69ec30efb463d4844c80b10d)

### [Dependency Injection Finally Made Sense When I Stopped Thinking Like a Developer](https://ujjwalkar.hashnode.dev/dependency-injection-finally-made-sense-when-i-stopped-thinking-like-a-developer?utm_source=hashnode&utm_medium=feed)

A practical explanation of Dependency Injection, why writing extra interfaces matters, and how DI protects your code from future change.

3 min read · [ujjwalkar.hashnode.dev](https://ujjwalkar.hashnode.dev/dependency-injection-finally-made-sense-when-i-stopped-thinking-like-a-developer?utm_source=hashnode&utm_medium=feed)

[1](https://hashnode.com/posts/dependency-injection-finally-made-sense-when-i-stopped-thinking-like-a-developer/69907f42f6e377a8e908003a) [Feb 14](https://hashnode.com/posts/dependency-injection-finally-made-sense-when-i-stopped-thinking-like-a-developer/69907f42f6e377a8e908003a)

### [🧠 JavaScript Hoisting Explained Simply (With Examples)](https://ujjwalkar.hashnode.dev/javascript-hoisting-explained-simply-with-examples?utm_source=hashnode&utm_medium=feed)

Master how var, let, const, and function declarations behave behind the scenes — and avoid common pitfalls in your JS code.

5 min read · [ujjwalkar.hashnode.dev](https://ujjwalkar.hashnode.dev/javascript-hoisting-explained-simply-with-examples?utm_source=hashnode&utm_medium=feed)

[Jun 10, 2025](https://hashnode.com/posts/javascript-hoisting-explained-simply-with-examples/68489592141f5bce84e2bad4)

### [Avoid this 10 common mistakes React Developers while writing useState.](https://ujjwalkar.hashnode.dev/avoid-this-10-common-mistakes-react-developers-while-writing-usestate?utm_source=hashnode&utm_medium=feed)

Enhance Your React Skills with Best Practices. Avoid These 10 Common Mistakes to Write Cleaner, More Efficient Code

2 min read · [ujjwalkar.hashnode.dev](https://ujjwalkar.hashnode.dev/avoid-this-10-common-mistakes-react-developers-while-writing-usestate?utm_source=hashnode&utm_medium=feed)

[Nov 26, 2024](https://hashnode.com/posts/avoid-this-10-common-mistakes-react-developers-while-writing-usestate/6745d38f17f629d10d1e7315)