Module: Strings::Truncate

Defined in:
lib/strings/truncate.rb

Overview

A module responsible for text truncation

Constant Summary collapse

DEFAULT_TRAILING = 
"…".freeze
DEFAULT_LENGTH = 
30

Class Method Summary collapse

Class Method Details

.display_width(string) ⇒ Object

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Visible width of a string



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# File 'lib/strings/truncate.rb', line 102

def display_width(string)
  Unicode::DisplayWidth.of(Strings::ANSI.sanitize(string))
end

.shorten(original_chars, chars, length_without_trailing) ⇒ String

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Perform actual shortening of the text

Returns:

  • (String) 


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# File 'lib/strings/truncate.rb', line 71

def shorten(original_chars, chars, length_without_trailing)
  truncated = []
  return truncated if length_without_trailing.zero?
  char_width = display_width(chars[0])
  while length_without_trailing - char_width > 0
    orig_char = original_chars.shift
    char = chars.shift
    break unless char
    while orig_char != char # consume ansi
      ansi = true
      truncated << orig_char
      orig_char = original_chars.shift
    end
    truncated << char
    char_width = display_width(char)
    length_without_trailing -= char_width
  end
  truncated << ["\e[0m"] if ansi
  truncated
end

.to_chars(text) ⇒ Object

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future. 



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# File 'lib/strings/truncate.rb', line 94

def to_chars(text)
  UnicodeUtils.each_grapheme(text)
end

.truncate(text, truncate_at = DEFAULT_LENGTH, options = {}) ⇒ Object

Truncate a text at a given length (defualts to 30)

Examples:

text = "The sovereignest thing on earth is parmacetti for an inward bruise."

Strings::Truncate.truncate(text)
# => "The sovereignest thing on ea…"

Strings::Truncate.truncate(text, 20)
# => "The sovereignest t…"

Strings::Truncate.truncate(text, 20, separator: " " )
# => "The sovereignest…"

Strings::Truncate.truncate(text, 40, trailing: "... (see more)" )
# => "The sovereignest thing on... (see more)"

Parameters:

  • text (String) —

    the text to be truncated

  • truncate_at (Integer) (defaults to: DEFAULT_LENGTH) —

    the width at which to truncate the text

  • options (Hash) (defaults to: {}) —

    @option options [Symbol] :separator the character for splitting words @option options [Symbol] :trailing the character for ending sentence



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# File 'lib/strings/truncate.rb', line 42

def truncate(text, truncate_at = DEFAULT_LENGTH, options = {})
  if truncate_at.is_a?(Hash)
    options = truncate_at
    truncate_at = DEFAULT_LENGTH
  end

  if display_width(text) <= truncate_at.to_i || truncate_at.to_i.zero?
    return text.dup
  end

  trail      = options.fetch(:trailing) { DEFAULT_TRAILING }
  separation = options.fetch(:separator) { nil }
  sanitized_text = Strings::ANSI.sanitize(text)

  length_without_trailing = truncate_at - display_width(trail)
  chars = to_chars(sanitized_text).to_a
  stop  = chars[0, length_without_trailing].rindex(separation)
  slice_length = stop || length_without_trailing
  sliced_chars = chars[0, slice_length]
  original_chars = to_chars(text).to_a[0, 3 * slice_length]
  shorten(original_chars, sliced_chars, length_without_trailing).join + trail
end