Generate random alphanumeric string in Ruby (v < 2.5)

secure_random.rb

# Ruby(2.4.4) Module - SecureRandom - https://ruby-doc.org/stdlib-2.4.4/libdoc/securerandom/rdoc/SecureRandom.html
SecureRandom.class_eval do 
  
  CHARSET = [*"A".."Z", *"0".."9"]

  # Returns Randomly generated 6 or more char long alphanumeric string
  def self.alphanumeric(number)
    CHARSET.sample(number).join
  end
end


## Sample -
# Generate 6 chars long random alphanumeric string
# > SecureRandom.alphanumeric(6)