Daily Coding Challenges & Projects

Frontend Mini Project Challenge

Bring together JS, CSS, React or Vue

Project :

Dark Mode Toggle / Theme Changer

• Build a toggle to switch between light & dark themes.
• Persist the user’s preference using localStorage.
• Use CSS variables (--bg, --text) to define themes.
• Enhance with a smooth transition for theme switch (e.g., .5s fade).

Try it on : CodeSandbox or StackBlitz

Backend Challenge

Scala, Swift (Vapor), TypeScript (Node.js), R

Scala Task :

Write a small CLI tool to parse a CSV of sales data and compute total sales per category using functional style (e.g., map, groupBy).

Swift (Vapor) Task :

Create a Vapor server with a GET endpoint /status returning JSON { status: "OK", timestamp: ... }.

TypeScript (Node.js) :

Build a small Express API with TypeScript to manage tasks: GET /tasks, POST /tasks, data stored in-memory.

R Task (data-focused) :

Load a dataset in R, calculate the mean and median of a numeric column, and plot a histogram.

Database Query Challenge

Problems on SQL - HR Database :

1. Find departments with more than 10 employees.
2. Identify employees with no projects assigned (in a join table employee_projects).

Data Structures & Algorithms Challenge

• Easy:
• Problem :Reverse the kth node from the end in a linked list.
• Hint :Use a single pass or sort and return index 1.
• Medium:
• Problem : Implement a min-queue using two stacks that supports enqueue, dequeue, and retrieving min in O(1).
• Hard:
• Problem :Solve "Longest Palindromic Substring" — dynamic programming or center expansion.

Bug of the Day

Language : Python / PHP

Python Bug

Buggy Code:

def add_items(lst=[]):
    lst.append(1)
    return lst
print(add_items())  # called twice

Issue : Why does list grow between calls? Fix it.

PHP Bug

Buggy Code:

function half($x) {
  return $x / 2;
}
echo half("abc");

Issue : PHP warns or returns unexpected — add type validation.

📋 Daily Micro-Project

Budget Tracker :

Task :

• Build a simple budget tracker UI in React or Vue.
• Users can add expense/income items.
• List items with category, amount.
• Show total balance and total expenses.

Trivia: 5 Fun Facts

1. Scala was launched in 2004 by Martin Odersky.
2. Vapor is a server-side Swift framework introduced in 2016.
3. R originated in the 1990s by Ross Ihaka and Robert Gentleman.
4. TypeScript was created by Microsoft and released in 2012.
5. Functional programming is a key paradigm in both Scala and R.

Tool & Resource of the Day

Tool : Postman

Great for testing APIs and automating requests.

Resource Roundup :

• Vapor Docs (Swift backend)
• Scala by Example
• R for Data Science (ebook)

Interview Question of the Day

Daily Interview Questions

Frontend ( General ) :
1. How do you manage themes in React or Vue?
2. Explain localStorage and its persistence scope.

Backend ( Scala / Swift / TypeScript ) :
1. What is Akka in Scala and why use it?
2. Explain the Swift Vapor request pipeline.
3. What are benefits of TypeScript over plain JavaScript?

Database :
1. What is the difference between HAVING and WHERE?
2. When do you use a LEFT JOIN vs INNER JOIN?

Others :
1. Define “functional programming.”
2. What are “goroutines” equivalent in other languages?

Daily Quiz Challenge

Frontend :

1. Write CSS variables to define dark/light theme toggles.
2. How do you store theme preference in browser memory?
3. Which React hook is best for persisting side-effects?

Backend :

1. How do you parse JSON in Vapor?
2. What is TypeScript’s interface, and how’s it different from type?

Database :

• Query that counts projects per department.

Mixed Quiz :

1. Drive code differences between let/var/const in JS.
2. PL/SQL – when do you use GROUP BY?
3. Functional languages – what's an immutable data structure?

Weekly Cross-Domain Activities ( July 18 to July 24, 2025 )

API of the Day:

JokeAPI : Build a random joke app with categories and flags (NSFW filter).

Linux/DevOps Tip :

Use htop, iotop, and iftop to monitor CPU, disk, and network usage on Linux servers.

Real-World Project of the Week ( July 18 to July 24, 2025 )

Project of the Week:

Build a Task Manager App

• Use React + Express + MongoDB
• Support CRUD: Tasks with due dates, priority, and status
• Implement filters (Today, Completed, Priority)

Collaborative Project:

Start a GitHub repo for this task manager and invite others to contribute (issues, PRs, README).

Case Study:

Analyze the GitHub UI/UX — Can you recreate the repository page using frontend tools?