What refactoring is

What is refactoring?

• It is changing the code without altering its behaviour and improving its current structure
• A good programmer is the one that write code that human can understand and it is easy to change

Why refactor is needed?

• Code needs to be easy to modify, to understand and to transmit intention of the feature
• A poorly designed system is hard to change
• Economical benefits are obtained due to features are delivered faster

Drawbacks of refactoring?

• Refactors that make code more understandable may introduce a decay on the performance. After the refactor, you can measure it with profilers.
• Stakeholders want code that works, not one that would please an academic

When to apply refactoring?

• When programming you have to add a new functionality or refactor. You need to choose if it is the moment of applying a refactor. Most of the times it will be.
• Follow the boyscout rule: leave code better than when you found it
• If some code is messy but doesn't affect the current development, it is not mandatory to refactor it
• Sometimes you can't refactor and code needs to be done from scratch
• Refactoring doesn't imply making changes foreseeing the future (Yagni, You Are not Gonna Need It)

How to apply effectively refactoring?

• Refactor methodologies need to be applied in small substantial changes. Make a small modification, test it and commit it locally. If some error happens, rollback to previous commit

• You need solid self-checking tests in order to make sure your changes do not break anything. Continuous integration is a great companion.

• Complicated pieces of code need to be broken down and set a name for each of them

• Legacy code without tests is a big drawback, you need tests

• Most of IDEs will help you with refactoring

• A refactor is needed when you identify a piece of code that may lead to some misunderstanding or improvement. It is also known as Code Smells