Duplicated Code

One of the first principles we’re taught as developers: Don’t Repeat Yourself

Symptoms

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

Solutions

• Extract Method⭐ for duplicated code in the same file.
• Extract Class⭐ for duplicated code across multiple files.
• Extract Partial for duplicated view and template code.
• Replace Conditional with Polymorphism for duplicated conditional logic.
• Replace Conditional with Null Object to remove duplicated checks for nil value.