Clean Code PHP

Clean code is code that is easy to understand and easy to change. Even bad code can function. But if code isn't clean, it can bring a development organization to its knees.

Table of Contents

1. Introduction
2. Variables
   • Use meaningful and pronounceable variable names
   • Use the same vocabulary for the same type of variable
   • Use searchable names (part 1)
   • Use searchable names (part 2)
   • Avoid nesting too deeply and return early (part 1)
   • Avoid nesting too deeply and return early (part 2)
   • Avoid Mental Mapping
   • Don't add unneeded context
3. Naming
   • Avoid disinformation
   • Adjust the length of a name to the size of its scope
   • Methods should have verb names
   • Classes should have noun names
   • Boolean Variables/Functions should have a is/has/can prefix.
4. Comparison
   • Use identical comparison
   • Null coalescing operator
5. Comments
   • Multiline Comment vs. Single-Line Comment
   • Nonlocal Comment
   • Never, Ever, Ever Comment Out Code!
   • Don’t Make Comments Harder Than the Code
   • Never Comment the Obvious
   • Always try to explain yourself in code
   • Avoid redundant comments
   • Give up mandated comments
   • Don't make noise
   • Avoid closing brace comments
   • Avoid position markers
   • Avoid HTML comments
   • Don't give too much information
   • Explaining Unclear Code
   • TODO Comments
   • Use reference links for codes
6. Functions
   • Use default arguments instead of short circuiting or conditionals
   • Function arguments (2 or fewer ideally)
   • Function names should say what they do
   • Functions should only be one level of abstraction
   • Don't use flags as function parameters
   • Avoid Side Effects
   • Don't write to global functions
   • Encapsulate conditionals
   • Avoid negative conditionals
   • Avoid conditionals
   • Avoid type-checking (part 1)
   • Avoid type-checking (part 2)
   • Remove dead code
7. Objects and Data Structures
   • Use object encapsulation
   • Make objects have private/protected members
8. Classes
   • Prefer composition over inheritance
   • Avoid fluent interfaces
   • Prefer final classes
9. SOLID
   • Single Responsibility Principle (SRP)
   • Open/Closed Principle (OCP)
   • Liskov Substitution Principle (LSP)
   • Interface Segregation Principle (ISP)
   • Dependency Inversion Principle (DIP)
10. Don’t repeat yourself (DRY)