Code refactoring is basically the process of restructuring an application’s code without changing it. It also doesn’t add up to its behavior and functionality. Its purpose is to make the code more efficient and easily maintainable. How can you refactor the code, what are the detailed benefits, and how can you go about it? Here’s the list of everything you need to know, including best practices.
Table of contents
- What is the meaning of code refactoring?
- What are the benefits of code refactoring?
- When should you go with software refactoring?
- Main techniques to perform a code refactor
- Best code refactoring tools
- Best practices to make it happen
What is the meaning of code refactoring?
We have already answered this question but the definition goes beyond simple restructuring. Reasons for the code being messy come from the developer’s inexperience, implementing shortcuts to meet tight deadlines, poor project management practices, or at least a few developers working on the same part of the project. It can also be a combination of all these factors.
As a result, you can get not only inefficient but also spaghetti code. Unnecessarily long and difficult to optimize. Without transparency, you can’t properly manage the app. Fix bugs, implement new functionalities, introduce integrations with third-party solutions.
Although code refactoring can help with bug fixing, it doesn’t mean you eliminate bugs during the process. You just prepare the ground. We can describe it as cultivating the field. As time goes by, weeds, bugs, and other unwanted elements plague your crops. You still have to get rid of them but it’s easier when you have a plan. When you respect the field and practice ecological and structured cultivation, bugs are fairly easily spotted. It’s also cheaper and healthier to get rid of them. You don’t have to use a flamethrower, sometimes all it takes is a penset.
OK, this metaphor can be overly enthusiastic but it’s true nonetheless. Code refactoring irons out the structure of the application, leaving healthy cells untouched and making room for repairs to be done.
Here are some code refactoring examples. Or rather types of a “dirty” code that leaves a mark on an app’s performance:
- unnecessary parts of code – removing them will not cause harm to the application
- areas of code that require multiple changes for other parts of the code to work properly
- tight coupling (you want low coupling and high cohesion)
- incorrect or incomplete application of object-oriented programming principles
- too large elements (code, methods, classes) that prevent easy manipulation
Code refactoring in these cases would consist of:
- removal of an unnecessary portion of the code
- simplifying code structure to ease cooperation between different portions of an application
- simplification and disconnecting elements
- proper implementation of object-oriented and functional programming principles
- shrinking the size and weight of elements in the code
Is code refactoring and code rewriting the same?
No, it’s not. These processes are both independent and different in nature.
Refactoring means that you restructure an existing project to make sure future updates will come smoothly. It can also mean using new versions of third-party libraries, frameworks, and technologies. It can also lead to lowering the level of code complexity.
Rewriting, on the other hand, means that you rewrite the application’s code from scratch. The entire process starts from the beginning, so developers are not limited by the existing code. That also means longer development time, since nothing is there.
What are the benefits of code refactoring?
One of the main clear benefits of code refactoring is that you’re removing underperforming portions of the code and replacing them with a more transparent one. Cleaning dirty code prepares your application for healthy performance. It also reduces your technical debt.
Clean code is easier to read. Not only for the person who actually wrote it. For other people too. As the number of engineers increases in the project, as more functionalities are added, as more QA specialists join the fold, as more integrations are rolling in, the harder it gets. What does what and why? How is this portion of code relevant to what I’m doing? Sure, you can fix some of it with code commentaries but it will not fix the fundamental problem – performance.
Clean code performs better. It also gives more insight into how the application is made. This leads to more informed decision-making. If a number of people understand how the software is built and what kind of architecture is used, they can think about future updates. They can also take ownership of future iterations and current changes, which is invaluable. Transparency encourages people to take responsibility, that’s a huge side benefit.
Another thing is multiplied importance. Sometimes applications have small pieces of code that have no front-end significance. Since they don’t “face the user”, nobody thinks of them as important enough to bother. Gather enough of these and you create a snowball effect. Sometimes unimportant, but sometimes with problems that can lead to enough work for two or even three people to manage and refactor.
This snowball effect can power up an entirely new approach to software development. It can, for example, spawn more coherent and regular code refactor initiatives, which we are sure everybody will appreciate. Especially when there is a lot to do. You don’t have to tackle everything at once. Sometimes it’s better to take things slow and fix one problem at a time. This will preserve the application’s stability and performance.
Another positive – “glass half full” approach. To give any kind of advantage, a rewrite must be completed. Refactoring doesn’t. You can stop in the middle of the process and still have a cleaner code. What you’re missing are a bigger picture and multiple benefits. What you’re losing is… nothing!
Also, updates. You can deliver updates to a user while still working on the code in the background. New features can be introduced through milestones but the code can get clean while you’re still working on the app. This is important for any kind of app, but with today’s complexities and product integrations with the cloud (Amazon Web Services, for example) it’s good to know that it’s business as usual.
When should you go with software refactoring?
The purpose of code refactoring is not to address bugs, so you shouldn’t do it while removing mistakes in your digital product. There are different ways to approach the topic and none of the schools has the ultimate tools.
We find it most practical to refactor the code before updating or adding new features. There’s also a policy to refactor during code review. It’s the last chance to correct some things before the product goes live. You can also implement a policy of regularly-scheduled refactoring sessions. This will take some time off your project’s calendar and prevent you from adding new elements as quickly as you probably wouldn’t, but it’s worth the trouble.
Regularity gives consistency. It prevents the code from becoming “muddy”. Engineers don’t have to spend a whole day refactoring. Instead, they only need hours at best. OK, but what about practical sense? When to actually go with code refactor?
You can start the process when:
- you spot logic repetition or declaration of code structures that go in circles
- multiple developers have trouble understanding the code and what it does
- multiple developers have issues with a portion of the code
- debugging takes longer than it should
- you’re debugging randomly because you have no idea how to tackle issues globally
- the last refactoring was some time ago and you’re due
- you’re planning to add a major feature, component, big block, or integration with a third-party solution
Also, consider using tools like SonarCloud or SonarQube. They measure the code’s duplication level, as well as cyclomatic complexity.
Main techniques to perform a code refactor
There are different ways to approach this process. Each of them works best under different circumstances, so you shouldn’t treat them as equal opportunities to achieve the same result. Match the best method for the task and issues at hand.
- Red-Green-Refactor. This is one of the most popular methods. By using this, developers break down the process into three stages.
- Stop and consider what needs to be developed. Also, write a test that will generate a fail (Red).
- Get the development to pass basic testing (Green).
- Implement improvements (Refactor).
The Red-Green-Refactor is a part of test-driven development (TDD); a foundation of Agile development.
2. Refactoring by abstraction. This method is used when there’s a huge amount of refactoring to do. The goal here is to reduce unnecessary duplications in code. Abstraction uses class inheritances, hierarchy, and extraction.
3. The composing method. Composing lets developers streamline the code to reduce duplications. To do that, they use processes like extraction and inline refactoring.
Extraction is based on breaking the code down into smaller parts to extract data fragmentation. Fragmented code is removed and replaced with a new piece of code. Inline, on the other hand, is used to reduce the number of unnecessary methods. It can greatly simplify the code.
4. Simplifying methods. Simplifying is based on polishing interactions between classes. It’s about adding, removing, and injecting new parameters while removing old ones at the same time.
It’s a good method to deal with an old code, which tends to gather “mud” and become inefficient simply by putting too much weight over time.
5. Moving features between objects. With this method, developers create new classes and move functionalities between old and new classes. When one class is “overweight”, some functionalities are dropped and moved to another one to compensate for inefficiency.
At the same time, if a given class is not busy, engineers can consolidate functionalities in one class and remove unused classes for code clarity.
6. Preparatory refactoring. One can argue that this one is actually a part of a software update rather than an element of a classic refactoring itself. It’s because a developer goes with preparatory refactoring when it’s time to introduce a new feature.
In this approach, refactoring is done on the go and as a reason to avoid technical debt in the future. It’s a great way to quickly iron out some portions of the code, but it’s even better to plan this ahead and not refactor last minute when the change is introduced to the application.
As you can see, there is a variety of options. Choose the one that will work best for you. That should always depend on the size and scope of the project, the time you have for running refactoring, the number of people that can help you, and the state of the code itself.
The best part is that the previously mentioned six methods for code refactoring are not the only ones. In fact, there are dozens more; you can find them on Refactoring.com. Some of them are so unique or based on exotic assumptions that we didn’t want to spoil the overall meaning of this article.
Best code refactoring tools
There are many code refactoring tools, but it’s best to focus on automated ones. Sure, they will not do everything and you still have to control them and measure results. The difference is that these will definitely simplify the process and generate more time for other activities.
You can choose your refactoring tool from these:
There are other choices, but these are essentials.
Best practices to make it happen
There are some handy pointers you can use for a positive experience. For example – always try to break down the code into smaller chunks for better management and issue visibility. Also, remember about documentation. It’s not only for your benefit but also for those who will come after.
Plan your code refactoring ahead. Not only when you introduce new and major features. Try to stay ahead of the game and predict bottlenecks. Refactor to avoid pitfalls.
Make code refactoring a part of your bloodstream. Refactor often, but with a carefully executed plan. Prepare tests for the process and use them frequently. If something slips by, change testing methods. Don’t throw a towel after one or two occurrences. Refactor regularly.
Because refactoring can affect outcomes in a product, involve Quality Assurance specialists. It’s always a good idea to make them part of the process. In-depth and regression testing can be a part of the refactoring process. Be on QA’s good side and cooperate with them on a daily basis. You never know what they could find and you never know what can be unintentionally missed.
Also, use previously mentioned tools. Refactoring automation can help in all kinds of projects and situations. Especially when you need a full-scale, end-to-end development. The more complexity in a project, the more you’re vulnerable. Refactor often and automate what you can.
Refactoring at Code & Pepper
At Code & Pepper, we approach code’s quality seriously. We identify challenging problems from the very beginning. Those that can generate technological debt, for example. First of all, we set up tools to help us with the process.
We use Prettier for code formatting, ESLint for problem identification, SonarCloud/SonarQube for continuous inspection of code quality (including code duplication). We also make code review for every Pull Request. Becauce the opportunity is there, we also do refactoring. These are just the beginning. Our teams periodically engage with code reviews. They leave comments in the code, that helps a lot. Usually there are two developers for code reviews, that minimizes risks of something going wrong.
We also write unit and integration tests. Developers also set up tools to automatically measure code coverage. Usually, coverage is set to 70%. That way we have a necessary confidence level. At the same time, the team isn’t forced to write tests just to bump statistics. If we do write tests, it’s automatic end-to-end (E2E) tests with Cypress, Playwright or Detox.
Having a good testing base is a huge advantage. Developers are not afraid to approach refactoring. They have a lot of experience and confidence regarding the rest of the application. They can easily test and change something, without the fear of messing up the entire product.
Technological debt is an issue of its own. We have to talk about it – openly and early on. That way our developers will have time to deal with it. Our approach? Once in a while we do a sprint dedicated to elimination of the technological debt and nothing else. Through refactoring, of course. Sometimes it’s hard to talk about it with the client. It requires argumentation and patience. The important part is time. Future functionalities hop into the project faster and smoother. That’s a final conclusion and a real benefit.
The structure of a code is the beast that must be tamed. Refactoring gives tools to have everything in order and be ready for the future. No matter what tool or good practice you will choose for the project, it’s always best to have a good team to work with. Software can’t be built and enhanced just like that. It needs consistency and talent.
You can build a product from scratch or augment your existing talent pool. Either way, the future of your app starts today. Are you confident you’re ready for it?