javascript toISOString() ignores timezone offset [duplicate]

Question

moment.js is great but sometimes you don't want to pull a large number of dependencies for simple things.

The following works as well:

    var tzoffset = (new Date()).getTimezoneOffset() * 60000; //offset in milliseconds
    var localISOTime = (new Date(Date.now() - tzoffset)).toISOString().slice(0, -1);
    
    console.log(localISOTime)  // => '2015-01-26T06:40:36.181'

The slice(0, -1) gets rid of the trailing Z which represents Zulu timezone and can be replaced by your own.

My solution without using moment is to convert it to a timestamp, add the timezone offset, then convert back to a date object, and then run the toISOString()

var date = new Date(); // Or the date you'd like converted.
var isoDateTime = new Date(date.getTime() - (date.getTimezoneOffset() * 60000)).toISOString();

moment.js FTW!!!

Just convert your date to a moment and manipulate it however you please:

var d = new Date(twDate);
var m = moment(d).format();
console.log(m);
// example output:
// 2016-01-08T00:00:00-06:00

http://momentjs.com/docs/

This date function below achieves the desired effect without an additional script library. Basically it's just a simple date component concatenation in the right format, and augmenting of the Date object's prototype.

 Date.prototype.dateToISO8601String  = function() {
    var padDigits = function padDigits(number, digits) {
        return Array(Math.max(digits - String(number).length + 1, 0)).join(0) + number;
    }
    var offsetMinutes = this.getTimezoneOffset();
    var offsetHours = offsetMinutes / 60;
    var offset= "Z";    
    if (offsetHours < 0)
      offset = "-" + padDigits(offsetHours.replace("-","") + "00",4);
    else if (offsetHours > 0) 
      offset = "+" + padDigits(offsetHours  + "00", 4);

    return this.getFullYear() 
            + "-" + padDigits((this.getUTCMonth()+1),2) 
            + "-" + padDigits(this.getUTCDate(),2) 
            + "T" 
            + padDigits(this.getUTCHours(),2)
            + ":" + padDigits(this.getUTCMinutes(),2)
            + ":" + padDigits(this.getUTCSeconds(),2)
            + "." + padDigits(this.getUTCMilliseconds(),2)
            + offset;

}

Date.dateFromISO8601 = function(isoDateString) {
      var parts = isoDateString.match(/\d+/g);
      var isoTime = Date.UTC(parts[0], parts[1] - 1, parts[2], parts[3], parts[4], parts[5]);
      var isoDate = new Date(isoTime);
      return isoDate;       
}

function test() {
    var dIn = new Date();
    var isoDateString = dIn.dateToISO8601String();
    var dOut = Date.dateFromISO8601(isoDateString);
    var dInStr = dIn.toUTCString();
    var dOutStr = dOut.toUTCString();
    console.log("Dates are equal: " + (dInStr == dOutStr));
}

Usage:

var d = new Date();
console.log(d.dateToISO8601String());

Hopefully this helps someone else.

EDIT

Corrected UTC issue mentioned in comments, and credit to Alex for the dateFromISO8601 function.

It will be very helpful to get current date and time.

var date=new Date();
  var today=new Date(date.getTime() - (date.getTimezoneOffset() * 60000)).toISOString().replace(/T/, ' ').replace(/\..+/, '');  

Using moment.js, you can use keepOffset parameter of toISOString:

toISOString(keepOffset?: boolean): string;

moment().toISOString(true)