The aim of this article is to help software engineers learn what code refactoring means, why it is essential to developers, and the best practices programmers can use to successfully refactor code and make their code readable, understandable, scalable, and testable.
When working in applications, you might often encounter the dreaded code rot. Code rot can occur from poorly written code. The solution to this is code refactoring. This article presents a discussion on what code refactoring is, when and when not to do code refactoring, and the strategies and best practices for refactoring your code.
What is Code Refactoring?
Code refactoring is a process that alters previously written code, keeping the functionality intact. In other words, code refactoring is a strategy that, when applied, improves the internal structure of a system without altering the external behavior of the code. It is a restructuring process that improves the code’s readability, extensibility, and maintainability. It is a process used to clean up code while at the same time ensuring that the functionality is not changed. While code refactoring doesn’t eliminate or eradicate bugs, it can help in preventing bugs in the future.
The Pitfalls of Refactoring Code the Wrong Way
Despite all of its benefits, you should take utmost care when refactoring code. Improperly refactored code can inadvertently affect the application’s functionality and introduce bugs that did not exist in previous editions. In addition, refactoring code improperly might also degrade the application’s performance.
Another good time for code refactoring is after you’ve delivered the product. This is a perfect time to refactor the code since your developers can spend some time refactoring and adjusting their code before they are assigned new tasks.
When Don’t You Need to Refactor Code?
Refactoring code is not a good choice when you would like to revamp the application from the beginning. It is better to start from scratch; you don’t need refactoring here. You might not want to refactor the code when there is already a tight deadline. Refactoring is not well suited in this scenario since it would take more time to refactor the code and then test the application after refactoring. Hence this might lead to additional costs for your client regarding time and money, which might not be acceptable.
Contrary to code rewriting, refactoring preserves the behavior of the code, i.e., it remains the same. You should not refactor the code if you don’t have tests to claim or guarantee that the behavior of the code hasn’t been affected because of refactoring.
Best Practices for Code Refactoring
There are a number of best practices and recommendations for refactoring code. This section talks about these practices.
Understand the Code
This is a significant undertaking you should consider before you start refactoring the code. First, you should review the source code to understand how the classes, methods, and objects work in the application. You must understand the flow of the application as well; a sequence diagram can help you understand the flow of the method calls and their sequence better – consider using one.
Set Clearly Defined Objectives
You should specify a clearly defined scope and targets before starting on the code refactoring process to avoid delays. It would be best if you considered what and what not to refactor before refactoring. Set schedules and delivery targets that can align with the current workflow, such as the CI/CD process being used in the organization. Set crisp and well-defined objectives that are not dependent on other tasks.
Although cleaning up code is essential, it is a time-consuming and costly affair. It would help if you refactored when you know that the code can be made efficient, readable, and maintainable with a modest developer effort. The best time to refactor the code is just before any new feature is introduced to the code. Then, you can clean up the current code before new features are added. This would decrease the amount of technical debt to be dealt with in the future.
Balance Deadlines and Technical Debt
Although it is a good idea to refactor code before new features are introduced, if you are going to refactor pieces of code before new features are added to the application, it can help reduce the technical debt. Still, it can be costly in terms of the extra time it would take to get the product to the market. There might be tight deadlines, and you might not follow this practice in reality often – you need to keep a balance to be successful.
Practice Consistent Coding Practices
You should be able to bring consistent coding practices to the table. All developers should use consistent coding techniques. Add meaningful comments and indentation wherever needed. Line spacing and other readability formatting standards should be adhered to as well. Once the overall coding approach is streamlined, it will be easier to write, change and maintain your code.
Remove Code Duplication
One of the candidates for refactoring is duplicate methods – you might have several methods that do the same task. However, identical methods or code duplication can expand the software’s footprint and add complexity as well. As a result, testing, debugging, and troubleshooting can become problematic. Instead, you should combine similar methods into one to reduce the lines of code in the program, make the code easier to understand, test, and maintain.
Test, Test and Test – Early and Often
Although code refactoring doesn’t alter the functionality, it still requires test coverage to ensure none of the program’s functionality was altered.. Hence you must test the code after refactoring to ensure it hasn’t introduced any additional bugs. If the tests fail, then most likely, the refactored code has introduced bugs. So, as soon as you or your developer has refactored a piece of code, test it.
Use the Right Tools to Improve Code
It would be best if you also took advantage of the right tools that can improve code quality. Such tools will help speed up the refactoring process and identity issues in code that might get unnoticed otherwise. In addition, most modern-day code editors and Integrated Development Environments (IDEs) help ensure that consistent coding standards and guidelines are followed.
Code Refactoring Summary
Refactoring is seldom a one-time effort. Instead, it should be an ongoing maintenance project. You should refactor code to clean the code and improve the code quality often. It would help if you also thought of automating the refactoring process as much as possible. Developer IDEs such as Eclipse and IntelliJ IDEA have built-in support for automated code refactoring. You can also use IntelliCode in Visual Studio to help in the code refactoring process.
Written by Joydip Kanjilal. Microsoft Most Valuable Professional, Author & Speaker. Winner of Community Credit Awards and MSDN Featured Developer of Fortnight.