Refactoring – the key to clean code

Learn all about code refactoring in this guide! Discover how to turn a chaotic warehouse into a perfectly organised storehouse and finally put everything back in its place.

Imagine your code is like an old warehouse: clean and organised at first, but now a chaotic mess. Refactoring brings order to this chaos, improves code quality and enables your team to work efficiently without encountering unexpected problems.

Learn all about code refactoring in this guide! Discover how to turn a chaotic warehouse into a perfectly organised storehouse and finally have everything back in its place.

Refactoring means ‘restructuring’ – which pretty much explains it all.

When refactoring code, the existing code is restructured in many small steps, known as refactorings, without changing its basic functionality. The aim is to make the code easier to understand and thus enable resource-efficient further development in the long term.

In practice, this means that the code is tidied up and the software quality is improved without the users of the system noticing any changes in functionality. This includes, for example:

• renaming variables,
• introducing new abstractions,
• reducing nesting depth and
• removing unused code.

The aim is to model the technical and domain language as clearly as possible so that teams always remain capable of acting and can integrate new functions.

Imagine your code is like a library. At first, all the books are neatly sorted on the shelves: novels, non-fiction and crime novels all have their designated places. But over time, books are simply put down anywhere and no one knows where to find anything anymore. Annoying, right?

But there's no need to start from scratch with a completely new software development project, because that's where refactoring comes in. Code that isn't maintained over a long period of time can become just as chaotic as the library mentioned above. In this case, the code quality deteriorates significantly, understanding disappears and complexity increases.

At this point, at the latest, complaints about so-called ‘spaghetti code’ start to pile up. And for good reason! This causes a significant increase in implementation effort, makes troubleshooting more difficult and prevents efficient work. In short: it leads to increasing paralysis.

Let's be honest: stakeholders want new requirements to be implemented quickly, easily and cost-effectively. A confusing and difficult-to-understand code base is more of a hindrance than a help, which is why the importance of refactoring in software development should not be underestimated.

Whether for debugging, implementing new features or during a review, refactoring should be considered at every stage of software development. This is because it offers a number of advantages that improve the software:

• Reduced complexity and comprehensibility: The complexity of the code is reduced, making it easier to understand. This facilitates teamwork and simplifies maintenance.
• Testability: A clearer structure ensures better testability and helps to identify errors at an early stage.
• Debugging: Bugs can be found and fixed more quickly because the code is clearer.
• Resource conservation: An optimised code base reduces resource consumption and increases efficiency.

And the best thing about it: Refactoring can be done during ongoing development without interrupting the development process.

There are numerous methods for restructuring existing code. However, the following six approaches are a good place to start:

• Rename: Rename variables, methods or classes to make them more meaningful and understandable.
• Embed: Move compact and understandable code directly to the location where it is needed, rather than outsourcing it to methods or variables.
• Extract methods: Move complex and confusing code segments into separate methods and describe them with meaningful method names.
• Move to local variables: Instead of leaving values without context in the code, it makes sense to store them in descriptive variables. For example, 3.14 should be referred to as PI.
• Add parameters: If data changes frequently within a method, it should be passed as a parameter. This extends the parameter list and reduces the need to modify the method.
• Move to field: Move recurring values in a class to a common field to simplify maintenance.

These methods should be selected and applied as needed and according to project requirements.

As Goethe once said: One size does not fit all. The same applies to code refactoring.

This means that there is no standard procedure that is suitable for every project. Each project requires individual measures to be defined: what needs to be restructured, how and to what extent. Since there is no one-size-fits-all solution, this is intended as a rough guide.

At MaibornWolff, however, we place great value on transparency and knowledge transfer: That is why we accompany you from the very beginning on your way to a maintenance-friendly, resource-saving and future-proof application. With our decades of experience in software development and in performing our software health checks, we tailor the following approach to your individual needs – whether for new applications or for old, difficult-to-maintain monoliths.

After this introduction, it comes as no surprise that the first step in refactoring is to gain an overview of the existing code and the underlying processes. To do this, the most important metrics should be analysed first, such as:

• cyclomatic complexity,
• nesting depth,
• test coverage,
• file sizes and
• the number of functions and classes.

Large and complex files can be an initial indication of code that is difficult to understand and modify.

This analysis makes it possible to view the applications in isolation and make further decisions. In this step, it should also be clarified which quality assurance processes, such as code reviews, already exist.

Based on the information from the previous step, a decision is made as to which parts of the code should be restructured as a priority or as part of daily work. Transparency is crucial here: it is not important how the code arrived at its current form, but how the existing problems can be solved.

Prioritisation is followed by integration. It is important to note that refactoring is most effective when integrated into daily development work. This includes:

• implementation,
• debugging and
• testing.

However, every rule has its exceptions: particularly incomprehensible or complex code passages must be isolated and restructured separately. The areas affected by this have already been identified during prioritisation.

A major challenge in software refactoring is not to change the existing functionality of the code. To achieve this, you need good test coverage to check the functionality before and after refactoring. This process can be perceived as additional effort, but in fact it is simply an important part of quality assurance in code refactoring.

Now that you have determined which parts of the application should be isolated and prioritised, it is time to start refactoring these parts. Once the scope has been defined, all affected code locations are revised systematically rather than incrementally, i.e. step by step. Only when these isolated code locations have been successfully restructured is the rest of the code tackled.

This question is not looking for someone to blame, and that's a good thing. Because there is no clear answer to the question of why code becomes chaotic over time. But one thing is certain: most developers write good code and know that refactoring is a necessary part of development.

But how does confusing, complex and chaotic code come about? Well, nobody works in a vacuum. Developers not only have to write clean code, they also have to:

• deal with external influences,
• overcome entrenched processes,
• take industry-specific requirements into account,
• gain the understanding and trust of stakeholders, and
• reconcile different interests.

A real Herculean task, in other words. To make matters worse, refactoring often only shows its added value after some time and can further complicate implementation.

This is where two worlds collide: on the one hand, there is good code and maintainability; on the other, there is the desire to implement requirements as quickly as possible.

That is why refactoring is not about assigning blame, but about openly addressing problems and finding solutions. This is also our motto at MaibornWolff. Together, we create a project that you and your team can be proud of.

Refactoring therefore improves code quality and readability, which in turn improves the speed at which requirements are converted into revenue. So far, so good. But what's the catch?

To answer this question, we need to look at two different levels of challenges: the technical and the human.

The technical challenges of refactoring often begin before the actual process. The harsh reality is that the longer you put off refactoring, the worse the code becomes – especially in large projects.

The problem grows unnoticed, increasing maintenance costs and the likelihood of errors. Now you are faced with a decision: refactoring or no refactoring.

Decisions, decisions. If you decide to refactor your software, these are the challenges you will face:

• Maintain functionality: Restructuring code without changing its functionality sounds simple, but it can be very difficult.
• Increased coordination required: Extensive refactoring requires increased communication between developers to ensure that all changes are implemented correctly. This takes time and can lead to lengthy discussions.
• Need for testing: To ensure functionality, extensive testing must be carried out before refactoring, which means additional effort.
• Merge conflicts: Working in branches can hinder refactoring, as developers fear merge conflicts that can arise when merging code changes.
• Quality assurance and test coverage: A lack of confidence in quality assurance or incomplete test coverage means that developers are reluctant to modify the code for fear of impairing functionality.
• Long reintegration times: Major changes resulting from refactoring can lead to long reintegration times, which often has a deterrent effect and delays the process.

But as is so often the case, the human factor comes into play alongside the technical aspects. Ultimately, it is people who need to be convinced of the benefits of refactoring and who make the final decision. And this is where the first challenges arise:

• Gradually visible changes: Changes resulting from refactoring often only become apparent gradually, which frequently leads to them being neglected or dismissed.
• Trust and time: Successful refactoring requires trust in the team and sufficient time to recognise the benefits of the changes.
• Experienced developers are necessary: It takes experienced developers to identify dependencies in the code and communicate the need for refactoring.
• Demonstrate responsibility: Clear communication of responsibility for refactoring code is crucial in order to schedule time for it, especially in complex projects.
• Understanding of ideal code structure: Even new code may require refactoring to meet long-term quality standards. Developers must develop a growing understanding of the ideal structure of the code and implement it in their work.

Well-organised code is like a well-oiled machine: when everything is in its place and clearly structured, development costs are not only plannable but also predictable. This allows you to focus fully on further development and innovation without being slowed down by unexpected obstacles. Refactoring is the key to a clean, efficient and future-proof code base.