Code Refactoring

Purpose

Improve code structure, readability, and maintainability without changing its external behavior or functionality.

When to Use

• Code is hard to understand or modify
• Duplicated code exists
• Functions are too long or complex
• Code smells are present
• Preparing for new features

Key Capabilities

1. Extract Method - Break long functions into smaller pieces
2. Rename - Improve variable/function names for clarity
3. Remove Duplication - Consolidate repeated code

Approach

1. Identify code that needs improvement
2. Ensure tests exist before refactoring
3. Make small, incremental changes
4. Run tests after each change
5. Commit working states frequently

Example

Before:

def process(data):
    result = []
    for item in data:
        if item > 0 and item < 100 and item % 2 == 0:
            result.append(item * 2)
    return result

After:

def is_valid_even_number(n):
    return 0 < n < 100 and n % 2 == 0

def process(data):
    valid_numbers = filter(is_valid_even_number, data)
    return [n * 2 for n in valid_numbers]

Best Practices

• ✅ Always have tests before refactoring
• ✅ Make small, incremental changes
• ✅ Run tests after each change
• ❌ Avoid: Refactoring and adding features simultaneously