code: async function codeGenerator(length = 6) {
      const code = new Array(length)
        .fill('0')
        .map(() => CHARS_SET[Math.floor(random() * (charsSetLength - 1))])
        .join('');
      log('debug', `Generated a new code:`, code);
      return code;
    }
docs: Returns a random code
  @param  {Number}   [length]
  An optional custon code length (defaults to 6)
  @return {Promise<String>}
  A promise of the generated code
  @example
  console.log([
  codeGenerator(),
  codeGenerator(),
  codeGenerator(),
  ]);
  // Prints: ABCDEF,GHJKMN,PRSTUV