Description
Refactoring is a systematic process of improving code without adding any new functionality, that can transform a messy, unmanageable code into clean code and simple design.
- Reduces technical debt.
- Improves code quality and readability.
- Makes the design simpler.
In this tutorial, we will go through everything you need to know about code refactoring in software development.
Clean Code
Clean code is something that all programmers wish to code and maintain, but we tend to handle a lot of messy code that someone else has coded.
Here is a list of features that a clean code must-have.
- Clean code is easy to understand, modify, and maintain.
- Clean code doesn't contain duplicates.
- Clean code contains a minimal number of classes and moving parts.
- Clean code passes all the tests.
- Clean code is easier and cheaper to maintain.
For more details about clean code, check this link.
Technical Debt
No doubt, all the programmers try to write the code the best that they can.
However, the code becomes messy and unmanageable over a period of time if we don't refactor the code periodically.
The word "technical debt" in regard to unclean code is first suggested by Ward Cunningham.
We can relate the "technical debt" to "bank debt" as below.
- When we take a bank loan, we don't pay principal but regularly pay interest, and if we don't regularly pay the interest, it may rack up so much that the amount of interest exceeds the principal, making the payment impossible.
- Similarly, we can temporarily speed up the project by skipping the tests, but it gradually slows down the project until we pay off the debt by writing test cases.
Here is a list of common reasons for technical debt.
- Business pressure
- Delayed Refactoring
- Lack of tests
- Lack of documentation
- Lack of interaction between team members
- Lack of compliance monitoring
- Lack of competence
- Lack of understanding of consequences of technical debt
- Long-term simultaneous development in several branches of the source code repository
- Failing to combat the strict coherence of components
For more details about technical debt, check this link.
When to Refactor?
Most of us know what refactoring is, but are not sure when to refactor the code.
Here is a list of some situations when we need to consider refactoring the code.
- Rule of Three
- When adding a new feature
- When fixing a bug
- During code reviews
For more details about when to refactor, check this link.
How to Refactor?
Refactoring should be done in a series of small changes, each making the code better than earlier without breaking the functionality.
Here is a list of things that make refactoring done the right way.
- Refactoring should make code cleaner than earlier.
- Refactoring should not add new functionality to the existing code.
- Refactoring should not break the existing functionality.
- Refactoring should not break the existing test cases.
For more details about how to refactor, check this link.
Code Smells
Code Smells are the indicators of problems within the source code, that need to be addressed during refactoring.
- They are easy to find and fix.
- But they may be just symptoms of the actual problem, that exists deep within the code.
Here is a list of common code smell types.
- Bloaters
- Object-Oriented Abusers
- Change Preventers
- Dispensables
- Couplers
For more details about code smells, check this link.
Refactoring Techniques
Refactoring Techniques describe the actual steps to refactor an existing code.
- Most refactoring techniques have both pros and cons.
- Each technique must be applied with caution, as it may degrade the performance if not properly used.
Here is a list of common refactoring techniques.
- Composing Methods
- Moving Features between Objects
- Organizing Data
- Simplifying Conditional Expressions
- Simplifying Method Calls
- Dealing with Generalization
For more details about refactoring techniques, check this link.
Overall
We now know what refactoring is and how can it help improve the code quality and its maintenance.