code: function checkString(i) {
    if (i >= tokensLength) {
      return 0;
    }
  
    if (tokens[i].type === TokenType.StringSQ ||
        tokens[i].type === TokenType.StringDQ) {
      return 1;
    }
  
    return 0;
  }
docs: Check if token is part of a string (text wrapped in quotes)
  @param {Number} i Token's index number
  @returns {Number} `1` if token is part of a string, `0` if not