SOLID Code Smells

gistfile1.md

Single Responsibility

A class should have one, and only one, reason to change.

• Large Class

  • You can't easily describe what the class does in one sentence.
  • You can't tell what the class does without scrolling.
  • The class needs to change for more than one reason.
  • The class has more than seven methods.
  • The class has a total flog score of 50.

• Divergent Change

  • You can't easily describe what the class does in one sentence.
  • The class is changed more frequently than other classes in the application.
  • Different changes to the class aren't related to each other

• Duplicated Code

  • You find yourself copying and pasting code from one place to another.
  • Shotgun surgery occurs when changes to your application require the same small edits in multiple places

Open/closed principle

You should be able to extend a classes behavior, without modifying it.

• Large Class

  • You can't easily describe what the class does in one sentence.
  • You can't tell what the class does without scrolling.
  • The class needs to change for more than one reason.
  • The class has more than seven methods.
  • The class has a total flog score of 50.

• Divergent Change

  • You can't easily describe what the class does in one sentence.
  • The class is changed more frequently than other classes in the application.
  • Different changes to the class aren't related to each other

Liskov substitution principle

Derived classes must be substitutable for their base classes.

• Explicit checking for type
  • is_a?
  • kind_of?
  • case
  • respond_to?

Interface segregation principle

Make fine grained interfaces that are client specific.

• ActiveRecord methods outside of ActiveRecord models.

Dependency inversion principle

Depend on abstractions (module or duck type), not on concretions (class).

• depend on things that change less often than you do
• Explicit checking for type
  • is_a?
  • kind_of?
  • case
  • respond_to?