Alternative moment.js

en.json

{
  "months": ["January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December"],
  "monthsShort": ["Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"],
  "weekdays": [
    { "index": 0, "label": "Sunday" },
    { "index": 1, "label": "Monday" },
    { "index": 2, "label": "Tuesday" },
    { "index": 3, "label": "Wednesday" },
    { "index": 4, "label": "Thursday" },
    { "index": 5, "label": "Friday" },
    { "index": 6, "label": "Saturday" }
  ],
  "weekdaysShort": [
    { "index": 0, "label": "Sun" },
    { "index": 1, "label": "Mon" },
    { "index": 2, "label": "Tue" },
    { "index": 3, "label": "Wed" },
    { "index": 4, "label": "Thu" },
    { "index": 5, "label": "Fri" },
    { "index": 6, "label": "Sat" }
  ],
  "weekdaysMin": [
    { "index": 0, "label": "Su" },
    { "index": 1, "label": "Mo" },
    { "index": 2, "label": "Tu" },
    { "index": 3, "label": "We" },
    { "index": 4, "label": "Th" },
    { "index": 5, "label": "Fr" },
    { "index": 6, "label": "Sa" }
  ]
}

formatter.js

const REGEX_FORMAT = /\[([^\]]+)]|Y{1,4}|M{1,4}|D{1,2}|d{1,4}|H{1,2}|h{1,2}|a|A|m{1,2}|s{1,2}|Z{1,2}|SSS/g;

const pad = (value) => {
  return `${value}`.padStart(2, '0');
};

const createOffset = (date) => {
  const sign = date.getTimezoneOffset() > 0 ? '-' : '+';

  const offset = Math.abs(date.getTimezoneOffset());

  const hours = pad(Math.floor(offset / 60));

  const minutes = pad(offset % 60);

  return `${sign}${hours}:${minutes}`;
};

const formatter = (date, format, schema) => {
  let calendarSchema = typeof schema === 'object' ? schema : require('./en.json');

  const $date = new Date(date);

  const $Y = $date.getFullYear();

  const $M = $date.getMonth();

  const $D = $date.getDate();
  
  const $W = $date.getDay();

  const $H = $date.getHours();
  
  const $h = $H % 12 === 0 ? 12 : $H % 12;

  const $m = $date.getMinutes();

  const $s = $date.getSeconds();

  const $ms = $date.getMilliseconds();

  const matches = {
    YY: String($Y).slice(2),
    YYYY: String($Y),
    M: $M + 1,
    MM: pad($M + 1),
    MMM: `${(calendarSchema.monthsShort || [])[$M]}`,
    MMMM: `${(calendarSchema.months || [])[$M]}`,
    D: $D,
    DD: pad($D),
    d: String($W),
    dd: `${(calendarSchema.weekdaysMin || [])[$W].label}`,
    ddd: `${(calendarSchema.weekdaysShort || [])[$W].label}`,
    dddd: `${(calendarSchema.weekdays || [])[$W].label}`,
    H: String($H),
    HH: pad($H),
    h: String($h),
    hh: pad($h),
    a: $h >= 12 ? 'pm' : 'am',
    A: $h >= 12 ? 'PM' : 'AM',
    m: String($m),
    mm: pad($m),
    s: String($s),
    ss: pad($s),
    SSS: String($ms),
    Z: createOffset($date),
    ZZ: createOffset($date).replace(/\:/g, ''),
  };

  return (format || 'YYYY-MM-DD[T]hh:mmZ').replace(REGEX_FORMAT, (match, $1) => $1 || matches[match]);
};

export default formatter;

Usage

formatter(new Date(2021, 0, 1));
/* current date in ISO8601, without fraction seconds e.g. '2021-01-01T12:00+07:00' */

formatter(new Date(2021, 0, 1), 'ddd DD/MM/YYYY hh:mm:ss:sss A Z');
/* 'Fri 01/01/2021 11:46:24:2424 PM +07:00' */

formatter(new Date(2021, 0, 1), '[YYYYescape] YYYY-MM-DDTHH:mm:ssZ[Z]');
/* 'YYYYescape 2021-01-01T00:00:00+07:00Z' */