Lakhveer Singh Rajput

The Ultimate Coding Rule Book

🚀 The Ultimate Coding Rule Book: Principles Every Developer Must Know! 💻✨

Whether you’re a beginner or a seasoned developer, writing good code is not just about making something work—it’s about making it clean, maintainable, and scalable. Great code isn’t written once; it’s read, improved, and extended multiple times. In this blog, let’s dive into the principles and coding rules that every developer should master 🏆. We’ll break down each principle with clear examples, and I’ll share pro tips to help you code like a true pro! 💡🔥

🧭 1. DRY – Don’t Repeat Yourself

“Every piece of knowledge must have a single, unambiguous, authoritative representation within a system.”

Repeating code is one of the biggest enemies of maintainability. Instead of copying and pasting logic across files, extract it into functions, modules, or classes.

💡 Example (Bad):

# Bad: Repeated logic in multiple places
def calculate_discount(price)
  price - (price * 0.1)
end

def calculate_special_discount(price)
  price - (price * 0.1) - 20
end

✅ Better:

# Good: DRY principle applied
def discount(price, extra = 0)
  price - (price * 0.1) - extra
end

🔥 Pro Tip: If you copy-paste a piece of code more than twice, it’s time to refactor it.

🧩 2. KISS – Keep It Simple, Stupid

Complex solutions are harder to debug and maintain. Simple code wins every time.

💡 Example (Bad):

// Bad: Over-engineered
function addNumbers(a, b) {
  return [a, b].reduce((sum, num) => sum + num, 0);
}

✅ Better:

// Simple and clear
function addNumbers(a, b) {
  return a + b;
}

🔥 Pro Tip: Before adding a new library or writing a fancy pattern, ask: ➡️ Can this be solved with fewer steps?

🧱 3. SOLID Principles 🏗️

SOLID is a set of 5 key principles for clean object-oriented design.

🔹 S – Single Responsibility Principle (SRP)

A class should have only one reason to change.

💡 Example:

# Bad: Handles both data and email
class User
  def save; end
  def send_email; end
end

✅ Better:

class User
  def save; end
end

class UserMailer
  def send_email(user); end
end

🔹 O – Open/Closed Principle

Classes should be open for extension, but closed for modification.

🔹 L – Liskov Substitution Principle

Subclasses should be replaceable with their parent class without breaking functionality.

🔹 I – Interface Segregation Principle

Clients shouldn’t be forced to depend on methods they don’t use.

🔹 D – Dependency Inversion Principle

Depend on abstractions, not concrete implementations.

🔥 Pro Tip: Follow SOLID to keep your code flexible and future-proof.

🕊️ 4. YAGNI – You Aren’t Gonna Need It

Don’t write code for features you think you might need later. Build only what’s required today.

💡 Example (Bad):

# Bad: Building future-proofing too early
def calculate_price(price, discount_type="seasonal", future_feature=None):
    pass

✅ Better:

# Only what is needed
def calculate_price(price, discount):
    pass

🔥 Pro Tip: Premature optimization is the root of complexity.

💡 5. Clean Code Principles ✨

Good code should be readable like a story.

✅ Rules for Clean Code:

• Meaningful Names: Use descriptive variable and method names.
• Small Functions: Keep functions short and focused.
• Consistent Formatting: Stick to a coding style guide.

💡 Example:

# Bad
def d(p)
  p * 0.18
end

# Good
def calculate_gst(price)
  price * 0.18
end

🔥 Pro Tip: Code is read 10x more than it’s written. Write for humans first.

🛠️ 6. Test-Driven Development (TDD) ✅

Write tests before writing code. This ensures fewer bugs and safer refactoring.

💡 Example:

1. Write a failing test.
2. Write just enough code to pass.
3. Refactor.

🔥 Pro Tip: Automated tests = confidence in deploying 🚀.

⚡ 7. Error Handling & Logging

• Handle exceptions gracefully.
• Log useful information for debugging.
• Never expose sensitive details.

💡 Example:

try:
    data = fetch_api()
except Exception as e:
    logger.error(f"API fetch failed: {e}")

🧠 8. Code Reviews & Pair Programming

Two pairs of eyes are always better than one 👀. Code reviews catch bugs and improve team learning.

🔥 Pro Tip: Be open to feedback. Great developers collaborate, not compete.

🎯 Tips to Code Like a Pro 💪

✅ Write self-documenting code (comments only when necessary). ✅ Use version control (Git is a must). ✅ Keep commits small and meaningful. ✅ Continuously refactor for clarity and performance. ✅ Stay updated with new frameworks, libraries, and tools.

💎 Final Words

Coding is an art 🎨 and a discipline ⚡. By following these principles—DRY, KISS, SOLID, YAGNI, and Clean Code—you’ll not only write software that works but software that lasts.

✨ Remember:

💡 Good code is like a good joke—if you have to explain it, it’s not that good!

🔗 Call to Action

💥 Which of these principles do you follow the most? 💥 Do you have a coding rule that changed your life? 💬 Share your experience in the comments and let’s build better code together! 💻🚀