Hash Key Conversions

gistfile1.rb

class Hash
  def to_underscore
    convert_keys(self, :underscore)
  end

  def to_camel_case
   convert_keys(self, :camelize, :lower)
  end

  def to_underscore!
    convert_keys!(self, :underscore)
  end

  def to_camel_case!
   convert_keys!(self, :camelize, :lower)
  end

  private

  def convert_keys(obj, *methods)
    case obj
    when Hash
      obj.inject({}) do |hash, (key, value)|
        value = convert_keys(value, *methods)

        _format_key_and_set_value(hash, key, value, *methods)
      end
    when Array
      obj.map { |m| convert_keys(m, *methods) }
    else
      obj
    end
  end

  def convert_keys!(obj, *methods)
    case obj
    when Hash
      obj.keys.each do |key, value = obj[key]|
        value = convert_keys!(value, *methods)
        obj.delete(key)

        _format_key_and_set_value(obj, key, value, *methods)
      end

      obj
    when Array
      obj.map { |m| convert_keys!(m, *methods) }
    else
      obj
    end
  end

  def _format_key_and_set_value(hash, key, value, *methods)
    case key
    when String
      hash[key.send(*methods)] = value
    when Symbol
      hash[key.to_s.send(*methods).to_sym] = value
    end
    hash
  end
end