Function parse

pkgs/core/src/parse/index.ts:361–532

(
  dateStr: string,
  formatStr: string,
  referenceDate: DateArg<DateType>,
  options?: ParseOptions<ResultDate>,
)

 * //=> Sun Feb 28 2010 00:00:00
 */
export function parse<
  DateType extends Date,
  ResultDate extends Date = DateType,
>(
  dateStr: string,
  formatStr: string,
  referenceDate: DateArg<DateType>,
  options?: ParseOptions<ResultDate>,
): ResultDate {
  const invalidDate = () => constructFrom(options?.in || referenceDate, NaN);
  const defaultOptions = getDefaultOptions();
  const locale = options?.locale ?? defaultOptions.locale ?? defaultLocale;

  const firstWeekContainsDate =
    options?.firstWeekContainsDate ??
    options?.locale?.options?.firstWeekContainsDate ??
    defaultOptions.firstWeekContainsDate ??
    defaultOptions.locale?.options?.firstWeekContainsDate ??
    1;

  const weekStartsOn =
    options?.weekStartsOn ??
    options?.locale?.options?.weekStartsOn ??
    defaultOptions.weekStartsOn ??
    defaultOptions.locale?.options?.weekStartsOn ??
    0;

  if (!formatStr)
    return dateStr ? invalidDate() : toDate(referenceDate, options?.in);

  const subFnOptions: ParserOptions = {
    firstWeekContainsDate,
    weekStartsOn,
    locale,
  };

  // If timezone isn't specified, it will try to use the context or
  // the reference date and fallback to the system time zone.
  const setters: Setter[] = [
    new DateTimezoneSetter(options?.in, referenceDate),
  ];

  const tokens = formatStr
    .match(longFormattingTokensRegExp)!
    .map((substring) => {
      const firstCharacter = substring[0];
      if (firstCharacter in longFormatters) {
        const longFormatter = longFormatters[firstCharacter];
        return longFormatter(substring, locale.formatLong);
      }
      return substring;
    })
    .join("")
    .match(formattingTokensRegExp)!;

  const usedTokens: Array<{ token: string; fullToken: string }> = [];

  for (let token of tokens) {