Common Coding Mistakes & How to Fix Them Fast

1. Not Handling Errors Properly​

   • The Mistake: Ignoring errors or using empty catch blocks.

   • The Fix: Always handle errors with meaningful messages and logging.

   • Example (JavaScript):
     try {
         let data = JSON.parse(userInput);
     } catch (error) {
         console.error("Invalid JSON format:", error.message);
     }

2. Hardcoding Values Instead of Using Constants​

   • The Mistake: Using raw values throughout your code (if (status === 1)).

   • The Fix: Define constants and use them for better maintainability.

   • Example (Python):
     ACTIVE_STATUS = 1
     if user.status == ACTIVE_STATUS:
         print("User is active")

3. ​Not Using Version Control Properly​

   • The Mistake: Committing directly to main or not using meaningful commit messages.

   • The Fix: Use branches (feature/login-system), and write descriptive commit messages (fix: corrected login authentication bug).

4. Writing Long, Unreadable Functions​

   • The Mistake: Functions that do too much, making debugging difficult.

   • The Fix: Follow the Single Responsibility Principle (SRP) and break large functions into smaller ones.

   • Example (JavaScript, Before & After):

     • // Bad
       function processOrder(order) {
           validateOrder(order);
           applyDiscount(order);
           updateStock(order);
           notifyUser(order);
       }

     • //
       Good (Split into smaller functions)
       function validateOrder(order) {...}
       function applyDiscount(order) {...}
       function updateStock(order) {...}
       function notifyUser(order) {...}
        

5. ​Ignoring Code Formatting & Indentation

   • The Mistake: Messy, inconsistent spacing and indentation.

   • The Fix: Use a formatter like Prettier (JavaScript) or Black (Python).

6. Inefficient Looping & Iterations​

   • The Mistake: Using unnecessary loops that slow down performance.

   • The Fix: Use built-in functions like map, filter, or reduce.

   • Example (Python):

     • # Bad
       doubled_numbers = []
       for num in numbers:
           doubled_numbers.append(num * 2)

     • # Good
       doubled_numbers = [num * 2 for num in numbers]

7. Not Closing Database or File Connections​

   • The Mistake: Forgetting to close resources, leading to memory leaks.

   • The Fix: Use context managers or proper cleanup.

   • Example (Python):
     with open("file.txt", "r") as file:
         data = file.read()  # Auto-closes file after use

8. Using Poor Variable Naming

   • The Mistake: Naming variables vaguely (x, temp).

   • The Fix: Use meaningful names (user_age, total_price).

9. ​Not Writing Tests

   • The Mistake: Skipping testing, leading to undetected bugs.

   • The Fix: Write unit tests with Jest (JavaScript) or PyTest (Python).

10. Not Keeping Code DRY (Don’t Repeat Yourself)

    • The Mistake: Copy-pasting code instead of reusing functions.

    • The Fix: Refactor repeated code into reusable functions.

Final Point!!

Avoiding these common coding mistakes will make your code cleaner, more efficient, and easier to maintain. Use best practices, test your code, and always keep learning!