Compressing a string, but without corner cases. - Ruby Solution

compress_string.rb

## Compressing a string, but without corner cases.
## e.g. aaaaaaaabbbbbbb ==> a8b7
## abcdef => abcdef

def compress_string(str)
  count = 1
  can_be_compressed = false
  compressed_string = ''

  i = 1
  while(i <= str.length) do
    if str[i - 1] == str[i]
      count += 1
      can_be_compressed = true if count > 1
    else
      compressed_string += str[i - 1]
      compressed_string += count.to_s unless count == 1
      count = 1
    end
     i += 1
  end

  if can_be_compressed
    return compressed_string
  else
    return str
  end
end

puts compress_string('abcaaabbb')
puts compress_string('abcdefgh')
puts compress_string('aaaaaaaabbbbbbb')