method

truncate_bytes

v7.2.3 - Show latest stable - Class: String

truncate_bytes(truncate_to, omission: "â¦")

public

Truncates text to at most truncate_to bytes in length without breaking string encoding by splitting multibyte characters or breaking grapheme clusters (“perceptual characters”) by truncating at combining characters.

>> "ðªðªðªðªðªðªðªðªðªðªðªðªðªðªðªðªðªðªðªðª".size
# => 20
>> "ðªðªðªðªðªðªðªðªðªðªðªðªðªðªðªðªðªðªðªðª".bytesize
# => 80
>> "ðªðªðªðªðªðªðªðªðªðªðªðªðªðªðªðªðªðªðªðª".truncate_bytes(20)
# => "ðªðªðªðªâ¦"

The truncated text ends with the :omission string, defaulting to “â¦”, for a total length not exceeding truncate_to.

Raises ArgumentError when the bytesize of :omission exceeds truncate_to.

# File activesupport/lib/active_support/core_ext/string/filters.rb, line 101
  def truncate_bytes(truncate_to, omission: "â¦")
    omission ||= ""

    case
    when bytesize <= truncate_to
      dup
    when omission.bytesize > truncate_to
      raise ArgumentError, "Omission #{omission.inspect} is #{omission.bytesize}, larger than the truncation length of #{truncate_to} bytes"
    when omission.bytesize == truncate_to
      omission.dup
    else
      self.class.new.force_encoding(encoding).tap do |cut|
        cut_at = truncate_to - omission.bytesize

        each_grapheme_cluster do |grapheme|
          if cut.bytesize + grapheme.bytesize <= cut_at
            cut << grapheme
          else
            break
          end
        end

        cut << omission
      end
    end
  end

truncate_bytes

Related methods