method

truncate_bytes

v6.1.3.1 - Show latest stable - Class: String

truncate_bytes(truncate_at, omission: "â¦")

public

Truncates text to at most bytesize 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 bytesize.

# File activesupport/lib/active_support/core_ext/string/filters.rb, line 95
  def truncate_bytes(truncate_at, omission: "â¦")
    omission ||= ""

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

        scan(/\X/) do |grapheme|
          if cut.bytesize + grapheme.bytesize <= cut_at
            cut << grapheme
          else
            break
          end
        end

        cut << omission
      end
    end
  end

truncate_bytes

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