Every client wants to have a great code that is easy to modify and maintain. Still, few people know what it takes to deliver such code and, what’s more important, what could be done to turn bad code into a good one. Here’s the approach that can help you refine code base of your app. It is called code refactoring.
Code refactoring along with code review can help you deal with over-complicated, poorly-written code that smells. Yes, code can have a bad smell. Look at the picture below, here’s how many bad smells code can have.
At the same time, code refactoring is not a magic pill. It is not always necessary to make refactoring and even if it is – then you should do it wisely. If someone said you need refactoring, better know what it is, before starting. Sometimes, you’ll just need to implement good code review practices.
What does code refactoring mean?
For starters, here’s a short definition of a code refactoring:
Code refactoring is a collection of small techniques for improving code that already written and working without changing what this code does.
Code refactoring is performed in a way of small changes into an existing code with the goal of improving it. Perhaps the best way to understand refactoring is by describing its goals.
Purpose of Code Refactoring
- Reduce the complexity of the code.
- Improve readability of the code.
- Improve source-code maintainability.
Sometimes code refactoring serves the same goal as code review – code maintainability improvement. With one core difference: code refactoring, opposed to code review, is performed AFTER the project is complete and running.
Code refactoring is often performed when transferring a project from one development team to another. At this step, the initial team simplifies the code, makes it clean, easy-digestible, and readable, so that the new one could easily understand it and make edits without fear of breaking something.
- Extend the capabilities of the application.
- Make recognizable design patterns.
- Provides higher flexibility to existing solutions.
Code-refactoring can be also performed by a new team. For instance, when you’re dealing with legacy code. Or if you want to improve existing software solution with new features. We usually perform refactoring before updating existing apps of our clients. For instance, if the library that is used in the app is outdated or not maintained by a provider, we find a new library and refactor existing software base so it would work correctly with the new solution.
- Refine internal software architecture.
- Discover system’s vulnerabilities.
- Reveal hidden / dormant bugs.
Refactoring Tip: If you have a big software project with many developers working on it, then it is advised to perceive code refactoring as a hygienic habit and perform it continuously.
Refactoring is exceptionally useful when you’re dealing with a huge corporate app that has thousands of lines of code, multiple functional modules, and entities. A small bug can easily go unnoticed in such complex environment. Which is why some companies perform refactoring in addition to Quality Assurance and Security Checks.
Code refactoring is also applied during test-driven development (TDD). And it’s one of the crucial element of such development approach.
TDD is a software development technique based on the repetition of very short development cycles: the creation of tests – development of code that will allow passing those tests – and refactoring of the code to comply with development standards.
Test-driven development is usually used when the functionality of an app is clearly described and measurable in form of tests. Such approach helps to limit the number of defects because, eventually, all code-base are covered by tests and you can always check if something is not working correctly.
In addition, by focusing on the test cases, the development team gains a better understanding of functionality it needs to deliver and delivers exactly what client needs. Unfortunately, writing down tests costumes extra time, which leads to 50% (on average) increase of time needed for development.
On the other hand, code can be written by low-level specialists, as it does not require to be of a high quality. The only requirement for the code is to pass the test. Then you can refine it by one high-level specialist. Of course, that is why test-driven development needs refactoring in order to put the code in order after all tests are passed
Code Refactoring Techniques
Different techniques are used for different situations. Just as you wouldn’t always use a hummer and then a screwdriver. There is no particular order to use these techniques. There are some best practices, but absolutely no fixed path for using these techniques.
There are more than 100 different refactoring methods. We’ll define only three core approaches and provide simple code refactoring examples that will give you a notion of how code refactoring works.
- Generalization and work with abstractions
Let’s say you have two similar methods that are used in two different cases. For example multiplication of two values. Then you can generalize it in “multiplication” method and use only specific values for each of cases.
Abstractioning enables more code sharing, leading to better maintainability as there is less code to write. This way developer can apply abstractions that already exist without coding from scratch.
Refactoring Tip: By eliminating duplicates or extensive code you will have to remember less about what your old code does.
- Extraction of code into larger pieces
Let’s say you have “Method 1” that is getting a little too long. You can find few lines of code that belong together. Separate those lines out into its own method. Call it “Method 2” and then insert it into the “Method 1”. That’s refactoring.
With this approach, you can break the code down into reusable semantic units, extract classes, methods, etc. In essence, breaking down code into smaller pieces that are more easily understandable is refactoring with extraction.
- Improvement of names and code locations
Developers can rename methods and classes in order to better describe their purpose, which is helpful when you passing code to the new team. Or they can move whole strings of code to a more appropriate class or even source file according to the architectural needs.
Refactoring Tip: refactoring techniques applied without thinking will hurt more than they help.
Software fails when it becomes so complex that it can no longer provide the additional features needed while remaining error-free. Refactoring is used to improve code design to make it extensible and easier to understand.
If you believe new features will be needed in the future and your current code won’t easily be able to accommodate those features – you should think of refactoring your code. Have a complex project and want to change the development team – contact us we’ll asses your code!