Methods in this book helps to make application:
- Testable;
- Refactorable;
- Easy to work with;
- Easy to maintain.
The author prefers and suggests the use of PSR-2 coding standards.
Summarized:
- writing good code is hard: if it were easy to be good at it, everyone would be good at it;
- writing bad code is easy: too easy to find bad code in PHP; too easy to suggest (via putting source code out there or writing tutorials) others write bad code; too easy for developers to never “level up” their skills;
- we can't test anything: it is nearly impossible to test poorly written code;
- change breaks everything: regression bug — is a bug caused after introducing new features, fixing other bugs, upgrading a library, changing configuration settings, etc.;
- we live or die by the framework: when writing software within a framework, your code is so embedded into that framework that you’re essentially entering a long term contract with that framework; but there is a way to write code, using a framework, in such a way that switching out the framework shouldn’t lead to a complete rewrite of the application;
- we want to use all the libraries: if you’ve littered your code base with usages of some library, you now have a time consuming process to run through to upgrade your application to use some other library; adapters and a good-written test suite for them will guarantee a minimal amount of work and bugs, respectively, when the time comes to replace the libraries.