timepiece/node_modules/date-fns/parse/_lib/parsers/MonthParser.mjs

import { numericPatterns } from "../constants.mjs";
import { Parser } from "../Parser.mjs";
import { mapValue, parseNDigits, parseNumericPattern } from "../utils.mjs";

export class MonthParser extends Parser {
  incompatibleTokens = [
    "Y",
    "R",
    "q",
    "Q",
    "L",
    "w",
    "I",
    "D",
    "i",
    "e",
    "c",
    "t",
    "T",
  ];

  priority = 110;

  parse(dateString, token, match) {
    const valueCallback = (value) => value - 1;

    switch (token) {
      // 1, 2, ..., 12
      case "M":
        return mapValue(
          parseNumericPattern(numericPatterns.month, dateString),
          valueCallback,
        );
      // 01, 02, ..., 12
      case "MM":
        return mapValue(parseNDigits(2, dateString), valueCallback);
      // 1st, 2nd, ..., 12th
      case "Mo":
        return mapValue(
          match.ordinalNumber(dateString, {
            unit: "month",
          }),
          valueCallback,
        );
      // Jan, Feb, ..., Dec
      case "MMM":
        return (
          match.month(dateString, {
            width: "abbreviated",
            context: "formatting",
          }) ||
          match.month(dateString, { width: "narrow", context: "formatting" })
        );

      // J, F, ..., D
      case "MMMMM":
        return match.month(dateString, {
          width: "narrow",
          context: "formatting",
        });
      // January, February, ..., December
      case "MMMM":
      default:
        return (
          match.month(dateString, { width: "wide", context: "formatting" }) ||
          match.month(dateString, {
            width: "abbreviated",
            context: "formatting",
          }) ||
          match.month(dateString, { width: "narrow", context: "formatting" })
        );
    }
  }

  validate(_date, value) {
    return value >= 0 && value <= 11;
  }

  set(date, _flags, value) {
    date.setMonth(value, 1);
    date.setHours(0, 0, 0, 0);
    return date;
  }
}