Yesterday I was looking at some Ruby code that had an initialize method like this:

def initialize(data)
  @data = data
  @data = Wrapper.new(data) if data.is_a? Hash
end

This code has hidden intent that could be easier to read. By assigning @data possibly twice it forces the reader to keep extra context in their head while reading and masks intent. The intent of this code is to assign @data with whatever is passed in, unless it’s a Hash, if it’s a Hash it’s supposed to be a Wrapper.

Let’s see if we can write this a little better to help bring that intent forward:

def initialize(data)
  @data =
    if data.is_a? Hash
      Wrapper.new(data)
    else
      data
    end
end

This has removed the double assignment and focused on the fact that @data is either going to be one or the other of something. One thing to note is this has added lines of code to the definition, but I feel they are worth it.

Another way you could layout this method and slim it down would be like this:

def initialize(data)
  @data = data.is_a?(Hash) ? Wrapper.new(data) : data
end

I am not a big fan of the above examle; but some might love it… Here would be my best solution idea for the code currently:

def initialize(data)
  @data = transform_format(data)
end
 
private
 
def transform_format(data)
  case data
  when Hash
    Wrapper.new(data)
  else
    data
  end
end

This adds even more lines! However, it adds more description into what is going on as well. @data is being transformed, and if you want to see what that means you can look at the method transform_format to see exactly what that means.