code: function getParseRegexForToken(token, config) {
      switch (token) {
          case "jDDDD":
              return parseTokenThreeDigits;
          case "jYYYY":
              return parseTokenFourDigits;
          case "jYYYYY":
              return parseTokenSixDigits;
          case "jDDD":
              return parseTokenOneToThreeDigits;
          case "jMMM":
          case "jMMMM":
              return parseTokenWord;
          case "jMM":
          case "jDD":
          case "jYY":
          case "jM":
          case "jD":
              return parseTokenOneOrTwoDigits;
          case "DDDD":
              return parseTokenThreeDigits;
          case "YYYY":
              return parseTokenFourDigits;
          case "YYYYY":
              return parseTokenSixDigits;
          case "S":
          case "SS":
          case "SSS":
          case "DDD":
              return parseTokenOneToThreeDigits;
          case "MMM":
          case "MMMM":
          case "dd":
          case "ddd":
          case "dddd":
              return parseTokenWord;
          case "a":
          case "A":
              return moment.localeData(config._l)._meridiemParse;
          case "X":
              return parseTokenTimestampMs;
          case "Z":
          case "ZZ":
              return parseTokenTimezone;
          case "T":
              return parseTokenT;
          case "MM":
          case "DD":
          case "YY":
          case "HH":
          case "hh":
          case "mm":
          case "ss":
          case "M":
          case "D":
          case "d":
          case "H":
          case "h":
          case "m":
          case "s":
              return parseTokenOneOrTwoDigits;
          default:
              return new RegExp(token.replace("\\", ""));
      }
  }
docs: **********************************
  Parsing
  **********************************