Crystal detects Emoji symbols in String

Problem is to identify unicode characters that has different byte size, but single symbol in render. Such of the symbols Emoji.

subject = "🇺🇦 Ukraine"
puts subject.size
> 10

puts subject.bytesize
> 16

puts subject.chars
> ['🇺', '🇦', ' ', 'U', 'k', 'r', 'a', 'i', 'n', 'e']

To help developers to skip building a big Regexp² to detect characters, introduced String::Grapheme¹.

puts subject.grapheme_size
> 9

puts subject.graphemes
> [String::Grapheme("🇺🇦"), String::Grapheme(' '), String::Grapheme('U'), String::Grapheme('k'), String::Grapheme('r'), String::Grapheme('a'), String::Grapheme('i'), String::Grapheme('n'), String::Grapheme('e')]

The result shows exactly the number of symbols to be rendered.

Example how Grapheme could be used. Here is original code:

result = ""
subject.each_char_with_index do |c, index|
  result += "<" if index == 2
  result += c
  result += ">" if index == 8
end
puts result
> 🇺🇦< Ukrain>e

and it converted to something very similar

index = 0
result = ""
subject.each_grapheme do |symbol|
  result += "<" if index == 2
  result += symbol.to_s
  result += ">" if index == 8
  index += 1
end
puts result
> 🇺🇦 <Ukraine>

References

https://crystal-lang.org/api/1.3.2/String/Grapheme.html