@accounter/client/src/helpers/dates.ts

import { format } from 'date-fns';

export const parseMonth = (month?: string): string | undefined => {
  if (!month) {
    return undefined;
  }

  const numMonth = Number(month);
  if (Number.isNaN(numMonth) || numMonth < 0 || numMonth > 12) {
    return undefined;
  }

  if (month.length === 1) {
    return `0${month}`;
  }

  return month;
};

export const parseYear = (year?: string): string | undefined => {
  if (!year) {
    return undefined;
  }

  const numYear = Number(year);
  if (Number.isNaN(numYear) || numYear < 2000 || numYear > 2030) {
    return undefined;
  }

  return year;
};

export function hashDateFormat(date: Date): string {
  return format(new Date(date), 'yyyy/MM/dd');
}

type addZero<T> = T | 0;
type oneToFour = 1 | 2 | 3 | 4;
type oneToNine = oneToFour | 5 | 6 | 7 | 8 | 9;
type d = addZero<oneToNine>;
type YYYY = `20${addZero<oneToFour>}${d}`;
type MM = `0${oneToNine}` | `1${0 | 1 | 2}`;
type DD = `${0}${oneToNine}` | `${1 | 2}${d}` | `3${0 | 1}`;

export type TimelessDateString = `${YYYY}-${MM}-${DD}`;