@mohamadkh75/react-native-jalali-datepicker/src/utils/utils.js

React Native Jalali DatePicker component for both Android and iOS

import { jalaaliMonthLength, toGregorian, toJalaali } from 'jalaali-js';
import { PERSIAN_DIGITS } from './constants';

const j2g = (date, dateSeparator) => {
  const splitted = date.split(dateSeparator);
  const year = parseInt(splitted[0]);
  const month = parseInt(splitted[1]);
  const day = parseInt(splitted[2]);

  const { gy, gm, gd } = toGregorian(year, month, day);
  return new Date(gy, gm - 1, gd);
};

const g2j = (date, dateSeparator = '-') => {
  const splitted = date.split(dateSeparator);
  const year = parseInt(splitted[0]);
  const month = parseInt(splitted[1]);
  const day = parseInt(splitted[2]);

  const { jy, jm, jd } = toJalaali(year, month, day);
  return fullDate(jy, jm, jd, '/');
};

export const today = () => {
  const currentDate = new Date().toISOString().slice(0, 10);
  return g2j(currentDate);
};

export const lastYear = () => {
  const currentDate = new Date().toISOString().slice(0, 10);
  const splitted = currentDate.split('-');
  const year = parseInt(splitted[0]) - 1;
  const month = splitted[1];
  const day = splitted[2];

  return g2j(`${year}-${month}-${day}`);
};

export const nextYear = () => {
  const currentDate = new Date().toISOString().slice(0, 10);
  const splitted = currentDate.split('-');
  const year = parseInt(splitted[0]) + 1;
  const month = splitted[1];
  const day = splitted[2];

  return g2j(`${year}-${month}-${day}`);
};

export const isBefore = (firstDate, secondDate, dateSeparator) =>
  j2g(firstDate, dateSeparator) < j2g(secondDate, dateSeparator);

export const isAfter = (firstDate, secondDate, dateSeparator) =>
  j2g(firstDate, dateSeparator) > j2g(secondDate, dateSeparator);

export const getDays = (year, month) => {
  const daysLength = jalaaliMonthLength(year, month);
  const { gy, gm, gd } = toGregorian(year, month, 1);
  const firstDayIndex = new Date(gy, gm - 1, gd).getDay();
  const startingEmptyDays = (firstDayIndex + 1) % 7;

  return [
    ...Array(startingEmptyDays).fill('.'),
    ...Array.from({ length: daysLength }, (_, i) => i + 1)
  ];
};

export const getYears = (min, max) => {
  const length = max - min + 1;

  return Array.from({ length }, (_, i) => min + i);
};

export const fullDate = (year, month, day, dateSeparator) =>
  `${year}${dateSeparator}${month < 10 ? '0' + month : month}${dateSeparator}${
    day < 10 ? '0' + day : day
  }`;

export const toPersian = num =>
  `${num}`
    .split('')
    .map(digit => PERSIAN_DIGITS[Number(digit)])
    .join('');