format date / es6 / case style

formatDate.js

/*
 * Date Format 1.2.3
 * (c) 2007-2009 Steven Levithan <stevenlevithan.com>
 * MIT license
 *
 * Includes enhancements by Scott Trenda <scott.trenda.net>
 * and Kris Kowal <cixar.com/~kris.kowal/>
 * and leplay <https://gist.github.com/leplay/e9fafa24e29d8bfe5688>
 *
 * Accepts a date, a mask, or a date and a mask.
 * Returns a formatted version of the given date.
 * The date defaults to the current date/time.
 * The mask defaults to formatDate.masks.default.
 */

var formatDate = (function () {
  var token = /d{1,4}|m{1,4}|yy(?:yy)?|([HhMsTt])\1?|[LloSZ]|'[^']*'|'[^']*'/g
  var timezone = /\b(?:[PMCEA][SDP]T|(?:Pacific|Mountain|Central|Eastern|Atlantic) (?:Standard|Daylight|Prevailing) Time|(?:GMT|UTC)(?:[-+]\d{4})?)\b/g
  var timezoneClip = /[^-+\dA-Z]/g
  var pad = function (val, len) {
    val = String(val)
    len = len || 2
    while (val.length < len) val = '0' + val
    return val
  }

  // Regexes and supporting functions are cached through closure
  return function (date, mask, style, utc) {
    var dF = formatDate

    // You can't provide utc if you skip other args (use the 'UTC:' mask prefix)
    if (arguments.length === 1 && Object.prototype.toString.call(date) === '[object String]' && !/\d/.test(date)) {
      mask = date
      date = undefined
    }

    // Passing date through Date applies Date.parse, if necessary
    date = date ? new Date(date) : new Date()
    if (isNaN(date)) throw SyntaxError('invalid date')

    mask = String(dF.masks[mask] || mask || dF.masks['default'])

    // Allow setting the utc argument via the mask
    if (mask.slice(0, 4) === 'UTC:') {
      mask = mask.slice(4)
      utc = true
    }

    var _ = utc ? 'getUTC' : 'get'
    var d = date[_ + 'Date']()
    var D = date[_ + 'Day']()
    var m = date[_ + 'Month']()
    var y = date[_ + 'FullYear']()
    var H = date[_ + 'Hours']()
    var M = date[_ + 'Minutes']()
    var s = date[_ + 'Seconds']()
    var L = date[_ + 'Milliseconds']()
    var o = utc ? 0 : date.getTimezoneOffset()
    var flags = {
      d: d,
      dd: pad(d),
      ddd: dF.i18n.dayNames[D],
      dddd: dF.i18n.dayNames[D + 7],
      m: m + 1,
      mm: pad(m + 1),
      mmm: dF.i18n.monthNames[m],
      mmmm: dF.i18n.monthNames[m + 12],
      yy: String(y).slice(2),
      yyyy: y,
      h: H % 12 || 12,
      hh: pad(H % 12 || 12),
      H: H,
      HH: pad(H),
      M: M,
      MM: pad(M),
      s: s,
      ss: pad(s),
      l: pad(L, 3),
      L: pad(L > 99 ? Math.round(L / 10) : L),
      t: H < 12 ? 'a' : 'p',
      tt: H < 12 ? 'am' : 'pm',
      T: H < 12 ? 'A' : 'P',
      TT: H < 12 ? 'AM' : 'PM',
      Z: utc ? 'UTC' : (String(date).match(timezone) || ['']).pop().replace(timezoneClip, ''),
      o: (o > 0 ? '-' : '+') + pad(Math.floor(Math.abs(o) / 60) * 100 + Math.abs(o) % 60, 4),
      S: ['th', 'st', 'nd', 'rd'][d % 10 > 3 ? 0 : (d % 100 - d % 10 !== 10) * d % 10]
    }

    var result = mask.replace(token, function ($0) {
      return $0 in flags ? flags[$0] : $0.slice(1, $0.length - 1)
    })

    if (style === 'upper') {
      result = result.toUpperCase()
    } else if (style === 'lower') {
      result = result.toLowerCase()
    }

    return result
  }
}())

// Some common format strings
formatDate.masks = {
  'default': 'ddd mmm dd yyyy HH:MM:ss',
  '24Hours': 'HH:MM:ss',
  shortDate: 'm/d/yy',
  mediumDate: 'mmm d, yyyy',
  longDate: 'mmmm d, yyyy',
  fullDate: 'dddd, mmmm d, yyyy',
  slashDate: 'yyyy/mm/dd',
  shortTime: 'h:MM TT',
  mediumTime: 'h:MM:ss TT',
  longTime: 'h:MM:ss TT Z',
  isoDate: 'yyyy-mm-dd',
  isoTime: 'HH:MM:ss',
  isoDateTime: "yyyy-mm-dd'T'HH:MM:ss",
  isoUtcDateTime: "UTC:yyyy-mm-dd'T'HH:MM:ss'Z'"
}

// Internationalization strings
formatDate.i18n = {
  dayNames: [
    'Sun', 'Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat',
    'Sunday', 'Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Friday', 'Saturday'
  ],
  monthNames: [
    'Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec',
    'January', 'February', 'March', 'April', 'May', 'June', 'July', 'August', 'September', 'October', 'November', 'December'
  ]
}

// For convenience...
// Date.prototype.format = function (mask, utc) {
//   return formatDate(this, mask, utc)
// }

export default formatDate