Encode and decode emoji unicode characters

emoji.rb

module Emoji
  # Emojis found from link below
  # https://raw.githubusercontent.com/omnidan/node-emoji/master/lib/emoji.json
  SYMBOL_LOOKUP = JSON.parse(File.read("#{Rails.root}/emoji.json"))
  STRING_LOOKUP = SYMBOL_LOOKUP.invert
  ALL_REGEXP = Regexp.union(STRING_LOOKUP.keys)

  def find(symbol)
    SYMBOL_LOOKUP[symbol.to_s]
  end

  def find_by_string(str)
    STRING_LOOKUP[str]
  end

  def encode(str)
    str.gsub(ALL_REGEXP) { |m| ":#{find_by_string(m)}:" }
  end

  def decode(str)
    str.gsub(/:([^\s:]?[\w-]+):/) do |match|
      (find(Regexp.last_match(1)) || match).to_s
    end
  end

  module_function :find, :find_by_string, :encode, :decode
end