Legacy Code Refactoring Techniques and Best Practices

Legacy Code Refactoring Techniques

Here in this article, we will see some of the best legacy code refactoring techniques and practices. Code refactoring helps you keep your code base secure, up-to-date, and easy to understand.

As your business expands, there’s a good probability that your code has been modified by several developers, and it’s no longer well-organized. This could result in more redundancy, more maintenance costs, and difficulty working with your application.

So, what can you do to fix a messy and outdated code? You can either rewrite your entire application or refactor your code. Rewriting may be simple but a longer process followed by a hefty cost. Instead, you can cut costs by refactoring the code, which is substantially less expensive but challenging. 

Also Read: Modifying Legacy Code? How to Avoid Breaking Functionality

What is Legacy code refactoring?

Refactoring legacy code involves enhancing an old piece of code’s structure without modifying its functionality. The primary goal of refactoring is to simplify complicated code so you can comprehend or use it more effectively.

To put it simply, Legacy code refactoring techniques help you to rearrange and change existing code without altering how it operates. It reduces errors and redundancies to make the code comprehensible and manageable. 

Code refactoring must be a regular procedure because it not only keeps the code up to date but also helps you to cut down the cost in the long term.

Why is code refactoring important?

All programmers must adhere to the principle that their code must be clear, well-organized, and comprehensible to others who will be working with it. Alongside this, to offer new features and security reasons, the system must be improved with time.

Sometimes the improvements are done in a way that increases the code complexity. And code refactoring can increase the readability and maintainability of the code. Refactoring transforms unclean, repetitive, and inefficient code into clean code. 

Additionally, it avoids the uniformity issue brought on by the large number of developers committing their code to a central repository. Refactoring is necessary to maintain the performance, security, and long-term quality of the code.

  • Easy Maintenance
  • Improves Code Readability
  • Reduces Memory Consumption
  • Cost savings in long term
  • Increased collaboration

When should you consider code refactoring?

The ideal moment to refactor a code is just before adding a new feature or any major update in code. Before adding new features, clean up the existing code to increase the quality of the final code and make it simpler for later developers to work on it.

How to perform code refactoring? 

The ideal approach to refactoring a code is to do it in small steps. Additionally, it is crucial to perform refactoring before any new features or update is incorporated. Refactoring the code shouldn’t alter how the product functions in any way.

Nevertheless, there are numerous legacy code refactoring techniques and methods available to refactor legacy code. Among the most well-liked are:

1. Red-green refactoring 

The Red-Green-Refactor is one of the most popular legacy code refactoring techniques in Agile development. It is performed by breaking the code into three steps. 

This approach is a good illustration of test-driven development (TDD) which involves writing the tests before writing the code.

  • Red: This Red stage is to create a test that will be used to guide how a feature is implemented. When the requirements are satisfied, the test will pass.
  • Green: In the Green stage, you write code to pass the test you created in the Red stage. Without being worried about the optimization, the objective is to write a solution.
  • Refactor: In the refactor stage, you can start considering how to put your code into practice more effectively and efficiently. Take a deep breath. Have a look at your code and think about how you can implement it optimally. And continue to repeat this. 

2. Abstraction refactoring

When the refactoring requirement is very large, branching by abstraction is an ideal technique. Abstraction seeks to minimize pointless repetitions in software programming.

We can illustrate the working of Abstraction refactoring through the Pull-Up/Push-Down technique. 

The Pull-Up method reduces code duplication by pulling individual pieces into a superclass. Later, It is transferred from a superclass to a subclass using the Push-Down method.

3. Moving Features Between Objects

Moving features between objects is another one of the most efficient legacy code refactoring techniques. It is done to address scattered functionality across many classes. 

This approach entails both the creation of new classes and the migration of functionality from the old to the new ones.

You shift some of the code from one class to another when it has too many activities going on. Alternatively, if a class isn’t working much, you can shift its features to another class and eliminate it entirely.

4. Simplifying Methods

Eliminating outdated code and streamlining the logic is crucial. The simplification refactoring technique takes care of the interaction between classes. The interface between classes and method calls is made simpler using the same. 

To make the procedure simpler, new variables are added, removed, replaced, and implemented.

Legacy code refactoring best practices

While planning to refactor your code, you must adhere to any one legacy code refactoring technique for better results.

Legacy Code Refactoring techniques

Also, there are several best practices and guides available regarding code refactoring. Applying the Agile technique, taking things one step at a time, then testing is one of the best methods. 

Other best legacy code refactoring practices include the following:

1. Understand your infrastructure

It’s crucial to carefully analyze the source code to make sure you comprehend the various parts of the application infrastructure before you begin refactoring the code.

Working efficiently with legacy code requires doing a thorough application audit since it gives you visibility into the broken flows and dependencies.

2. Plan your refactoring

Finding the time to do code refactoring properly is one of the most difficult aspects.

Ask yourself. Do you want to refactor and clean up the entire code or you just want to rename variables for better readability? What will be the timeframe and technique?

And keep in mind that it will take longer than you anticipate, so allow yourself extra time and make plans appropriately.

It is crucial to identify objectives and schedule particular tasks that fit with the existing workflow of your application. These objectives must be clearly stated and independent of other tasks.

3. Test frequently

Even though code refactoring will not change the program’s functionality, testing is still necessary to make sure the new code doesn’t cause any issues. This helps prevent making coding modifications that unintentionally alter how the product works.

4. Do not pick other tasks in between

Try to avoid combining code refactoring with other tasks like adding a new feature or fixing a bug. Your only focus should be to complete the refactoring in a fixed timeframe. You can make notes of new ideas and bugs that you can pick after the refactoring. 

5. Try refactoring tools to speed up the process

Additionally, it’s critical to employ tools that can expedite the restructuring of code and reduce the likelihood of errors being missed. Some of the tools that you can use are Rider, IntelliJ IDEA, Eclipse IDE, Visual studio intellicode and Spring Tool Suite 4. 

Conclusion – Legacy code refactoring techniques

Refactoring your legacy code can help you keep it organized and tidy. You stress less when the code is nicely organized and refactored since it is simpler to navigate and use. It also makes work simpler for a new developer to work on your code. 

You will reap the benefits of creating a healthy and productive environment by performing routine code checks and refactoring. We also discussed some of the best legacy code refactoring techniques that can help you achieve your code simplification goal quickly.