Today’s applications consist of a large amount of source code, which is essential for their proper functioning. The growing number of features in designed and deployed solutions, as well as the availability of a wide range of programming languages and tools, make it easier to create modern, fast, scalable, and extensible applications tailored to the needs of clients. However, this also requires efficient management of the source code.
In the case of developing certain applications, there is often a focus on quick implementation and the volume of source code can often hinder work and lead to mistakes and errors, ultimately consuming a lot of time for both developers and software testers.
To maintain high-quality software, ensure its readability and optimization, and eliminate unnecessary source code, it’s worth considering source code refactoring. When done correctly, it allows for a quick and effective improvement in the quality and efficiency of the source code of any software.
In this material, we will take a closer look at the concept of code refactoring. We will introduce refactoring techniques, explain the benefits of implementing code refactoring, outline what an effective refactoring process should entail, and present successful examples of code refactoring.
What is code refactoring?
Code refactoring is often mistakenly associated with rewriting an application from scratch. In practice, code refactoring, also known simply as refactoring, is a complex process of restructuring existing source code with the goal of improving its quality, readability, and maintainability while keeping the external behavior of the application and its functionality unchanged.
The use of source code refactoring is becoming increasingly popular and is now a classic, widely practiced technique in the field of programming. It allows for the improvement of source code quality without affecting its correctness. Effectively carrying out code refactoring enables increased code readability, the removal of unnecessary elements, organization of the source code, and improvement of its performance. As a result, working with refactored source code is faster, more enjoyable, and simpler. A properly executed refactoring process positively impacts code readability, which also helps avoid time-consuming errors and mistakes in the development or maintenance of an application.
Importantly, refactoring does not change the functionality of the code; it only alters its internal structure and organization. This allows a programmer to focus on improving code quality without the risk of introducing new errors.
When is it worth deciding to refactor code?
There are many reasons why it’s worth considering code refactoring. The primary symptoms indicating the need for the source code refactoring process are:
- Incorrect code architecture without a consistent structure – when the code is unreadable, hard to understand, or lacks a consistent structure, it’s worth considering refactoring. Improving code readability makes it easier to maintain, reduces the likelihood of errors, and facilitates collaboration with other developers.
- Outdated technological stack – there are situations where the technology stack used is outdated, making it difficult to add new features. Often, applications have a longer lifespan than the technologies they are built upon. The refactoring process allows us to migrate them to the latest technological solutions and improve compatibility with industry standards.
- Repetitive Code – If the code contains many repetitive sections, such as code blocks or functions, refactoring allows you to extract and replace them with a common shared section, increasing readability and reducing complexity.
- Changing Requirements – When new requirements or functionalities arise that require modifications to existing code, refactoring can facilitate the introduction of these changes. The improved code structure will make it more flexible and easier to modify.
- Testing Difficulties – When the code is difficult to test, for example, creating unit tests or automated integration tests is time-consuming, refactoring can help improve testability. A better code structure makes it easier to write tests and provides greater confidence that changes will not result in unexpected errors.
- Performance and Optimization – when an application’s code runs slowly or is not optimized, refactoring can help improve performance. You can identify code sections causing delays or having high computational complexity and optimize them, leading to better application performance.
- Preparation for Expansion – when further development of the application is planned with the addition of new features, it’s valuable to conduct refactoring to ensure scalability and code extensibility. The improved structure will facilitate and accelerate the implementation of new functions without losing the integrity of the existing code.
Why is refactoring important?
Source code refactoring is incredibly important from a business perspective. Optimizing source code can save time and financial resources, improve the comfort of working with the code, and prepare it for easier future development.
A correctly executed source code refactoring process can lead to:
- Easier application expansion.
- Improved collaboration between programmers.
- Minimizing the time spent discussing the source code and increasing the efficiency of work.
- Potential cost optimization through risk reduction, source code optimization, and reduced programmers’ working time.
- Shortening the deadlines for processing applications.
- Minimized errors.
- Enhanced application performance for users.
- Improving client relationships by delivering higher-quality services.
- Hardware resource optimization.
- Optimization of the use of hardware resources; and reducing the costs of IT infrastructure necessary to support the application.
Benefits of code refactoring
Both developers and users of the application itself benefit from the results of source code refactoring. This solution provides benefits for both software houses and programming departments, as well as customer organizations that commission the development of applications.
Some of the major benefits of applying refactoring include:
- Improved readability – refactoring improves the readability of code, making it more understandable and easier for programmers to analyze. Improved variable, function and class names, elimination of dead code and simplification of structure make the code more intuitive and easier to maintain.
- Facilitated Maintenance – refactoring makes code more structured and easier to modify. A clear, simple structure makes it easier to make changes, debug and troubleshoot, making it simpler, faster and, consequently, cheaper to implement new features. In addition, by removing code duplication, updating the application requires modifications in only one place.
- Improving performance – Improving performance can be one of the goals of refactoring. Optimizing code, eliminating unused code and improving algorithms can contribute to the speed and efficiency of applications. Good quality code has less computational load and uses fewer resources.
- Easier Testing – code refactoring makes it easier to write unit tests and automated integration tests. Through better structure and isolation of functions, testing of individual modules becomes easier.
- Increased flexibility and scalability – improved code structure enables easier addition of new functionality and expansion of the application. By extracting repetitive code into separate functions or classes, the code becomes more flexible and easier to adapt to changing requirements.
- Facilitating team collaboration – clear and well-organized code is more accessible to other members of the development team. Collaboration and working on code together become easier, as all developers have access to structured and well-described code, so they can quickly understand how it works.
Code refactoring techniques
There are numerous code refactoring techniques available in the market. The process of code refactoring is complex and tailored to the specific project; however, some of the most popular code refactoring techniques include:
- Extraction Method – involves extracting a portion of code from an existing function or method and placing it in a new function. This allows you to eliminate repetitive code and improves readability.
- Inline Method – is the opposite of the extraction method. It involves replacing a method call by directly inserting its code in the appropriate place. It can be used when the called method is one-liner or doesn’t add additional value.
- Change Method Signature – involves modifying the signature (parameters) of an existing method. This can include adding, removing, or modifying parameters. It requires adjusting all the places where this method is used.
- Conditional Transformation Method – is based on transforming complex conditional if-else statements into more understandable and simpler structures, such as switch statements or the use of polymorphism.
- Extract Class Method – used when a class has too many responsibilities or is overly complex. It involves extracting some fields and methods from an existing class and moving them to a new class, creating a better structure and hierarchy of classes.
- Dead Code Elimination Method – involves removing unused code that is no longer used by the program. This may include unused variables, unreachable conditional statements, or unused methods.
- Simplification Method – is based on simplifying complex code segments by using more concise and readable programming language constructs, such as shorthand conditional expressions, the ternary operator, lambda expressions, etc.
How to perform effective refactoring?
The process of refactoring source code is complex and critical to maintaining the continuity and efficiency of the application. Therefore, it should be carefully planned. To conduct effective code refactoring, you should plan the process considering:
- Planning – before starting refactoring, it is important to plan the process well. You should identify the specific goals and areas of code that need improvement, identify what changes need to be made and determine how they will affect the application’s performance. You should also make sure that appropriate safeguards, such as tests, are provided to protect against unwanted changes in code behavior during refactoring.
- Selecting appropriate refactoring techniques – there are many different refactoring techniques, such as method extraction, duplication elimination, signature change, etc. Choose the ones that best fit your goals and will improve the readability, maintainability, performance or testability of your code.
- Iterative approach – refactoring should be done step by step, in small iterations. You should choose specific sections of code to refactor and focus on them. You need to make sure that each iteration is thoroughly tested and checked to avoid introducing new bugs.
- Testing – before you start refactoring, you need to make sure that you have prepared adequate unit tests and/or integration tests to ensure that the changes you make do not cause unexpected side effects. Tests should be run regularly to monitor whether the code continues to work properly after each iteration of refactoring.
- Application of good programming practices – during refactoring it is necessary to apply good programming practices, such as clear naming, SOLID principles, use of design patterns, DRY (Don’t Repeat Yourself) principles, etc. You need to make sure the code is understandable, well divided into functions and modules, and avoid duplication of code.
- Monitoring and measuring effects – after refactoring, it is worth monitoring and measuring the effects. You should observe how the performance and maintenance of the code has changed after refactoring. If possible, the results should be compared with previous measurements to assess whether the refactoring brought the expected benefits.
- Teamwork – in a team of developers, it is useful to involve other team members in the refactoring process. Joint goal setting, task sharing and regular communication to monitor progress and share knowledge is essential throughout the refactoring process.
Source code refactoring is an continuous process
It’s important to remember that source code refactoring is a continuous process. The application should be regularly subjected to refactoring. After completing the initial refactoring process, it’s valuable to identify elements within the source code during ongoing work that can benefit from refactoring. This approach allows for continuous improvements and optimizations, preventing the accumulation of unreadable source code. It’s crucial to approach refactoring with diligence, test the changes, and be prepared to make corrections if necessary.
Practical examples of code refactoring
There are some examples presented below of simple source code refactoring that illustrate the benefits of conducting the process across an entire application.
- Simplification of conditions (Python)
Before refactoring:
def check_discount_eligibility(age, has_membership):
if age >= 60 and has_membership:
return True
else:
return False
After refactoring:
def check_discount_eligibility(age, has_membership):
return age >= 60 and has_membership
- Renaming variables to increase code readability (C++):
Before refactoring:
void f(int a, int b, int c) {
int x = a + b;
int y = x * c;
std::cout << "Result: " << y << std::endl;
}
After refactoring: :
void calculateAndPrintResult(int firstValue, int secondValue, int multiplier) {
int sum = firstValue + secondValue;
int result = sum * multiplier;
std::cout << "Result: " << result << std::endl;
}
- Using exception handling instead of try-catch blocks (PHP)
Before refactoring:
try {
// Code that performs operations that can raise exceptions
} catch (Exception $e) {
// Error handling
}
After refactoring:
try {
// Code that performs operations that can raise exceptions
} catch (SpecificException $e) {
// Handling a specific exception
} catch (AnotherException $e) {
// Handling of another specific exception
} catch (Exception $e) {
// Handling of other exceptions
}
The above examples illustrate several refactoring techniques, such as simplifying conditions, renaming variables and methods to enhance code readability, and using exception handling instead of try-catch blocks. These changes improve code clarity, maintainability, performance, and scalability, while also facilitating further application development.
Code refactoring in a nutshell
Code refactoring is the process of restructuring and cleaning up existing source code without changing its behavior from the user side. This process aims to improve the quality, readability, performance and maintenance of the code, as well as make it easier to extend and test applications.
The main reasons to conduct refactoring include performance enhancement, easier implementation of changes, code comprehension improvement, logical structure organization, and code duplication elimination. The refactoring process requires careful planning and analysis, choosing the right refactoring techniques and tools, and conducting appropriate tests to ensure that changes do not introduce errors in the source code.
Code refactoring is an important process that helps keep the source code in good shape, improves its quality and readability, and facilitates further development and maintenance of the application, which ultimately leads to project success and increased satisfaction of the development team.
