Posted on:September 5, 2023 | 3 min read

Strategic Refactoring of Legacy Codebase

As a developer, you’ve likely come across legacy code at some point in your career, most of the time updating legacy code can be a challenging task. I am recently working on refactoring of a legacy Laravel application.

Having dealt with such a challenge in the past, I thought it would be great to document the strategies and practices I have been following along — but first, let’s understand what legacy code is and why it may require refactoring.

What is Legacy Code

Legacy code refers to code that follows outdated software development practices, such as poor documentation, outdated or obsolete APIs, libraries, or third-party technologies. It may not follow modern design patterns, making it difficult to maintain and expand.

Legacy code may require refactoring as

sequenceDiagram participant Legacy as Legacy Code participant Developer as Developer participant TechnicalDebt as Technical Debt participant Maintainability Legacy ->> Developer: Add quick fix Legacy ->> Developer: Use outdated dependency Developer ->> TechnicalDebt: Accumulates over time TechnicalDebt-->>Maintainability: Makes code hard to maintain Maintainability-->>Developer: Require refactoring Developer-->>Legacy: Apply refactoring techniques Legacy-->>Developer: Code improved!

Strategic Refactoring

Here are few practices and strategies I have been following,

  1. Start small with isolated areas causing issues.
  2. Prioritize high impact areas like performance and security.
  3. Take a gradual approach, refactoring one area at a time.
  4. Simplify structure and improve readability by splitting complex code and using clear naming.
  5. Automate with tools like linters to reduce manual effort.
  6. Use built-in framework features to streamline development.
  7. Thoroughly test before deploying refactored code.
  8. Continuously monitor the logs for a couple of days after the deployment.
graph TB Start[Start Small] --> Focus[Focus on High-Impact Areas] Start --> Adopt[Adopt a Gradual Approach] Focus --> Simplify[Simplify Code Structure and Improve Code Readability] Adopt --> Simplify Simplify --> Automate[Automate Where Possible] Simplify --> Leverage[Leverage Framework's Built-In Features] Automate --> Test[Test Thoroughly] Leverage --> Test Test --> Monitor[Monitor Logs & Performance]

Conclusion:

Refactoring legacy code is achievable and delivers immense value. With a strategic, incremental approach focused on highest impact areas, you can extend the life of aging systems. The payoff is well worth the initial effort.

I’ve been sharing some PHPStorm tips on Twitter for efficiently refactoring code, like this recent tweet about mass refactoring in PHPStorm. You can follow me on Twitter, if you like my content.