Cookbooks
Ruby
Chapter 5. Good Coding Practices
Refactoring

Ruby:
Refactoring

How to:

Let’s go through an example of refactoring a Ruby method that calculates the sum of squares.

Before Refactoring:

def sum_of_squares(numbers)
  sum = 0
  numbers.each do |number|
    square = number * number
    sum += square
  end
  sum
end

puts sum_of_squares([1, 2, 3])  # Output: 14

After Refactoring:

def sum_of_squares(numbers)
  numbers.map { |number| number**2 }.sum
end

puts sum_of_squares([1, 2, 3])  # Output: 14

The refactored version uses Ruby Enumerables to express the same logic more succinctly and clearly. The map method transforms each element, and sum aggregates their values, removing the need for manual loop management and variable assignment.

Deep Dive

Refactoring has a rich historical context, stemming back to the early practices in the software development. Initial mentions can be traced back to the 1990s, with significant contributions made by Martin Fowler in his book “Refactoring: Improving the Design of Existing Code”, where he provides a catalog of patterns for refactoring. Since then, refactoring has become a cornerstone of agile development practices.

When we talk about alternatives to refactoring, we either need to consider a different approach like ‘Rewriting’, where you replace the old system in parts or entirely or adapt practices like ‘Code Reviews’ and ‘Pair Programming’ to improve code quality gradually. However, these aren’t replacements for refactoring; they complement the process.

In terms of implementation, Ruby provides an excellent and expressive syntax that often results in shorter, more readable code after refactoring. Key principles include DRY (Don’t Repeat Yourself), using meaningful names, keeping methods short and focused on a single task, and using Ruby’s Enumerable module effectively, as seen in the example above. Automated tools like RuboCop can also help programmers to identify spots in the code that could benefit from refactoring.

See Also

To dig deeper into refactoring in Ruby, check out these resources:

Organizing code into functions