timer.js

/**
 * For global date and time management methods.
 * @key SGT: Schemester Global Time: The global notation as YYYYMMDDHHmmSSmmm, in the order of year, month, day, hour, minutes, seconds, milliseconds.
 */
class Time {
  constructor() {
    this.keys = ["year", "month", "day", "hour", "minute", "second", "milli"];
  }
  /**
   * Returns days in given month of given year.
   * @param {Number} monthIndex The month index of which days to be returned (January = 0).
   * @param {Number} year The year in which the given month index is to be found.
   * @return {Number} Total days in given month index.
   */
  daysInMonth = (monthIndex = Number, year = new Date().getFullYear()) =>
    new Date(year, monthIndex + 1, 0).getDate();

  /**
   * Returns the current moment (or incremented) in SGT notation.
   * @param {JSON} increment int objects from any of ['year','month','day','hour','minute','second','milli'] for increment. If not provided, then no increment takes place.
   * @param {Boolean} string Returns string if true, defaults to false (Number).
   * @note The value returned could differ at two different instances because of the shift of milliseconds. Therefore, use a single instance of this method wherever possible.
   */
  getMoment(
    increment = {
      year: 0,
      month: 0,
      day: 0,
      hour: 0,
      minute: 0,
      second: 0,
      milli: 0,
    },
    string = false
  ) {
    if (!increment) increment = {};
    this.keys.forEach((k) => {
      increment[k] = increment[k] ? increment[k] : 0;
    });
    let currentTime = new Date();
    let currentOffset = currentTime.getTimezoneOffset();
    let ISTOffset = 330; // IST offset UTC +5:30
    let d = new Date(
      currentTime.getTime() + (ISTOffset + currentOffset) * 60000
    );
    let year = d.getFullYear();
    let month = d.getMonth();
    let day = d.getDate();
    let hour = d.getHours();
    let min = d.getMinutes();
    let sec = d.getSeconds();
    let milli = d.getMilliseconds();

    if (milli + increment.milli > 999) {
      milli = milli + increment.milli - 1000;
      sec++;
      while (milli > 999) {
        sec++;
        milli -= 1000;
      }
    } else milli += increment.milli;

    if (sec + increment.second > 59) {
      sec = sec + increment.second - 60;
      min++;
      while (sec > 59) {
        min++;
        sec -= 60;
      }
    } else sec += increment.second;

    if (min + increment.minute > 59) {
      min = min + increment.minute - 60;
      hour++;
      while (min > 59) {
        hour++;
        min -= 60;
      }
    } else min += increment.minute;

    if (hour + increment.hour > 23) {
      hour = hour + increment.hour - 24;
      day++;
      while (hour > 23) {
        day++;
        hour -= 24;
      }
    } else hour += increment.hour;

    if (day + increment.day > this.daysInMonth(month)) {
      day = day + increment.day - this.daysInMonth(month);
      month++;
      while (day > this.daysInMonth(month)) {
        month++;
        day -= this.daysInMonth(month);
      }
    } else day += increment.day;

    month++;
    if (month + increment.month > 12) {
      month = month + increment.month - 12;
      year++;
      while (month > 12) {
        year++;
        month -= 12;
      }
    } else month += increment.month;

    year += increment.year;
    return this.getTemplateNotation(
      year,
      month,
      day,
      hour,
      min,
      sec,
      milli,
      string
    );
  }

  getTemplateNotation(
    year,
    month,
    day,
    hour,
    minute,
    seconds,
    millis,
    string = false
  ) {
    if (month < 10) month = `0${month}`;
    if (day < 10) day = `0${day}`;
    if (hour < 10) hour = `0${hour}`;
    if (minute < 10) minute = `0${minute}`;
    if (seconds < 10) seconds = `0${seconds}`;
    if (millis < 10) millis = `00${millis}`;
    else if (millis < 100) millis = `0${millis}`;
    return string
      ? `${year}${month}${day}${hour}${minute}${seconds}${millis}`
      : Number(`${year}${month}${day}${hour}${minute}${seconds}${millis}`);
  }

  /**
   * @deprecated As of November 30, 2020 03:30 IST
   * @see Time.getMoment() method.
   * Returns the current moment in SGT notation.
   * @param {Boolean} stringForm Defaults to true. This ensures that returned time in SGT notation is of type string?true else type number?false.
   * @param {Number} dayincrement The number of days to be incremented in returned SGT time. Defaults to 0.
   */
  getTheMoment = (stringForm = true, dayincrement = 0) =>
    this.getMoment({ day: dayincrement }, stringForm);

  /**
   * @deprecated As of November 30, 2020 03:30 IST
   * @see Time.getMoment() method.
   * Gets current date time in SGT notation.
   * @param {Number} minuteIncrement The number of minutes to be incremented in returned timing. (default=0)
   * @returns current/incremented time in the SGT notation.
   */
  getTheMomentMinute = (minuteIncrement = 0, stringform = true) =>
    this.getMoment({ minute: minuteIncrement }, stringform);
}

module.exports = new Time();