closest web safe color

closest_web_safe.rb

WEB_SAFE_NUMBERS = [
  0,   # 00
  51,  # 33
  102, # 66
  153, # 99
  204, # cc
  255  # ff
]

def closest_web_safe_color(string)
  new_string = "#"

  string.gsub("#", "").downcase.scan(/.{2}/).each do |chunk|
    base_ten = chunk.to_i(16)
    closest_web_safe = WEB_SAFE_NUMBERS.min_by { |num| (base_ten - num).abs }
    closest_web_safe_hex = closest_web_safe.to_s(16)
    if closest_web_safe_hex == '0'
      closest_web_safe_hex *= 2
    end

    new_string << closest_web_safe_hex
  end

  new_string
end

require 'minitest/autorun'

class TestMoveZeroes < Minitest::Test
  def test_it_works
    assert_equal '#993300', closest_web_safe_color('#ae3312')
  end
end

__END__

"ae".to_i(16) => base 10 number
170.to_s(16) => hex string