JavaScript: Date Formatter Library

posted in: Dates, JavaScript | 0

Formatting a date into ISO standard in JavaScript can be a big hassle.
I found this library to assist in formatting dates quickly.

Usage:
Use the format(‘isoDate’) function to format the date to ISO standard

var date = new Date();
var y = date.getFullYear();
var m = date.getMonth();
var previous_month_start = new Date(y, m - 1, 1).format('isoDate'); // 3rd party library for formatting

var previous_month_end = new Date(y, m, 0).format('isoDate'); // 3rd party library for formatting

Function:

SOURCE:  http://blog.stevenlevithan.com/archives/date-time-format

/*
* Date Format 1.2.3
* (c) 2007-2009 Steven Levithan 
* MIT license
*
* Includes enhancements by Scott Trenda 
* and Kris Kowal <cixar.com/~kris.kowal/>
*
* 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 dateFormat.masks.default.
*/

var dateFormat = function () {
var token = /d{1,4}|m{1,4}|yy(?:yy)?|([HhMsTt])\1?|[LloSZ]|"[^"]*"|'[^']*'/g,
timezone = /\b(?:[PMCEA][SDP]T|(?:Pacific|Mountain|Central|Eastern|Atlantic) (?:Standard|Daylight|Prevailing) Time|(?:GMT|UTC)(?:[-+]\d{4})?)\b/g,
timezoneClip = /[^-+\dA-Z]/g,
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, utc) { var dF = dateFormat; // 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", d = date[_ + "Date"](), D = date[_ + "Day"](), m = date[_ + "Month"](), y = date[_ + "FullYear"](), H = date[_ + "Hours"](), M = date[_ + "Minutes"](), s = date[_ + "Seconds"](), L = date[_ + "Milliseconds"](), o = utc ? 0 : date.getTimezoneOffset(), 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]
};

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

// Some common format strings
dateFormat.masks = {
"default": "ddd mmm dd yyyy HH:MM:ss",
shortDate: "m/d/yy",
mediumDate: "mmm d, yyyy",
longDate: "mmmm d, yyyy",
fullDate: "dddd, mmmm d, yyyy",
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
dateFormat.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 dateFormat(this, mask, utc);
};

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