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What is Code Smell, an example with Ruby?

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Author: Himanshu Saxena

Views: 189

A code smell is a surface indication that usually corresponds to a deeper problem in the code. It doesn’t necessarily mean there’s a bug, but it suggests that the code could be improved for better readability, maintainability, or performance.

Example of Code Smell in Ruby

Let’s consider a common code smell: Long Method. This occurs when a method does too much, making it hard to understand and maintain.

Smelly Code

class Order
  def total_price
    total = 0
    items.each do |item|
      total += item.price
      if item.taxable?
        total += item.price * 0.1
      end
    end
    total
  end
end
In this example, the total_price method is doing multiple things: calculating the total price, checking if items are taxable, and adding tax. This makes the method long and complex.

Refactored Code

class Order
  def total_price
    items.sum { |item| item_total(item) }
  end

  private

  def item_total(item)
    total = item.price
    total += item.price * 0.1 if item.taxable?
    total
  end
end
Here, the total_price method is simplified by extracting the tax calculation into a separate item_total method. This makes the code cleaner and easier to understand.

Tools for Detecting Code Smells

There are tools like Reek that can help detect code smells in Ruby. Reek examines Ruby classes, modules, and methods, and reports any code smells it finds.

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