string to unicode conversion in ruby

string.rb

# config/initializers/string.rb

class String
  # TODO: Don't know how to convert to UTF-16BE encoding using built-in methods, and then arrive
  # at the result similar to: http://api.mvaayoo.com/unicodeutil/unicode.jsp
  def to_unicode
    unpack('U*').map { |i| i.to_s(16).rjust(4, '0') }.join
  end
end

Other solution, use codepoints method.
And first need convert string to UTF-8 or UTF-16BE.

class String
  def to_unicode
    encode('UTF-8').codepoints.map { _1.to_s(16).rjust(4, '0') }.join
  end
end