Daily Coding Challenges & Projects

Frontend Mini Project Challenge

Theme : JavaScript, CSS, React, Vue

Challenge :

Create a toggleable dark/light mode switch with persistence.

Requirements :

• Use localStorage to remember the selected theme
• Provide smooth CSS transitions
• Apply to entire page layout

Bonus : Add a button that shows sun/moon icons based on the theme.

Backend Challenge

Language Focus : Scala, R, Swift, TypeScript

R Task :

Parse a CSV file of employee data and generate department-wise statistics (e.g., avg. salary, count).

Bonus : Save the output in a new CSV.

Database Query Challenge

Problems on SQL - HR Database :

1. Write a SQL query to list employees who have the same job as their manager.
2. Write a query to find departments that have more than 3 employees with salary above the department average.

Data Structures & Algorithms Challenge

• Easy:
• Problem :Check if a number is a power of two.
• Hint :Use bitwise AND with (n - 1).
• Medium:
• Problem :Group anagrams from a list of words.
• Hint : Use sorted strings as hash keys.
• Hard:
• Problem :Implement an LRU (Least Recently Used) Cache.
• Hint :Use a doubly-linked list with a hashmap.

Bug of the Day

Language : Swift

Swift Bug

Buggy Code:

// What's wrong?
func greetUser(name: String?) {
    print("Hello, \(name.uppercased())!")
}

greetUser(name: nil)

Fix the bug. :

Hint : Optional binding?

📋 Daily Micro-Project

Backend Focus :

Task :

Create a Swift microservice with Vapor that logs HTTP requests and responses to a file.

Bonus: Add middleware for request timing.

Trivia: 5 Fun Facts

1. Java was originally called Oak.
2. Python's name was inspired by "Monty Python's Flying Circus."
3. TypeScript was developed by Microsoft in 2012.
4. The term “refactoring” was popularized in the 1990s.
5. Git was created by Linus Torvalds in 2005.

Tool & Resource of the Day

Tool : RunJS

A JavaScript playground for rapid prototyping.

https://runjs.dev

Resource Roundup : Frontend Challenges

• Frontend Mentor Walkthroughs – YouTube
• "Refactoring UI" – Design tips for devs
• Vue Mastery – Free beginner course

Interview Question of the Day

Daily Interview Questions

Frontend :
1. What are fragments in React and why are they useful?
2. Explain how the v-bind directive works in Vue.js.
3. What is the purpose of refs in Vue and React?
4. What’s the difference between display: none and visibility: hidden?

Backend :
1. What are goroutines and how do they work in Go?
2. Explain strong vs weak typing with examples.
3. What is the purpose of middleware in Node.js?
4. How do closures work in JavaScript?

Database ( SQL ) :
1. What is normalization? Why is it important?
2. How do foreign keys help maintain data integrity?
3. What’s a correlated subquery?

Others :
1. What is a cron job? Give an example.
2. What is the difference between Docker image and container?

Daily Quiz Challenge

Frontend Quiz :

1. What does ref do in Vue?
• Adds CSS
• Binds styles
• References DOM elements
• Imports components
2. React hooks allow you to:
• Manage lifecycle only
• Use state and other features
• Create class components
• Extend JSX
3. z-index in CSS controls:
• Grid size
• Stack order
• Border radius
• Width

Backend Quiz :

1. What is the correct keyword to declare a coroutine in Kotlin?
• async
• coroutine
• launch
• suspend
2. Which language uses pattern matching?
• Python
• Scala
• JavaScript
• C
3. What does await do in TypeScript?
• Blocks thread
• Handles exceptions
• Waits for a Promise
• Imports modules

Database :

1. Which SQL clause is used for aggregation?
• WHERE
• GROUP BY
• ORDER BY
• HAVING

General :

1. Which Linux command shows running processes?
• top
• whoami
• ps
• ls

Weekly Cross-Domain Activities ( July 11 to July 17, 2025 )

API of the Day:

Task : Build a stock price tracker using Twelve Data API.

https://twelvedata.com.

Linux/DevOps Tip :

Use htop instead of top for a better interactive process viewer.

Real-World Project of the Week ( July 11 to July 17, 2025 )

Project of the Week:

Build an Expense Tracker using React + Express + MongoDB.

Collaborative Project:

Join the GitHub project “open-budget-app” and contribute a budget visualization module

Case Study:

Analyze how GitHub Actions works and create a basic CI pipeline using YAML.