Refactoring Techniques

Overview

Refactoring improves internal code structure without changing external behavior.

Common Techniques

• Extract method
• Rename for intent clarity
• Replace conditional with polymorphism
• Introduce parameter object
• Remove dead code

flowchart TD
    A[Smelly Code] --> B[Small Safe Refactor]
    B --> C[Run Tests]
    C --> D[Improved Design]

Practical Example

Before:

if (user.Role == "ADMIN")
{
    discount = total * 0.20m;
}
else if (user.Role == "PREMIUM")
{
    discount = total * 0.10m;
}

After strategy extraction:

discount = discountPolicy.ForRole(user.Role).Apply(total);

Production Guidance

• Refactor in small commits with tests green
• Prioritize hotspots: frequent changes and incidents
• Pair refactoring with observability checks in critical paths

Common Pitfalls

• Refactoring large modules without test safety net
• Combining functional changes with structural cleanup
• Ignoring performance regressions during refactor

Key Takeaways

• Refactoring keeps code healthy and adaptable.
• Small, test-backed changes reduce risk.
• Hotspot-based prioritization maximizes impact.