I think you want to parse a date string like August 26, 2015 with a timezone of UTC+0000, i.e. as 2015-08-26T00:00:00Z. The best way to do that is to format the string correctly and use a reliable parser.
However, if you're going to parse the string to reformat it you might as well also create a Date while you're doing it.
You can't confidently parse the string with the Date constructor or Date.parse since the format is not supported by ECMA-262, so use a library for that or a simple function.
Date strings without a timezone are typically parsed as local, i.e. assuming the host system timezone (except in ECMAScript where, just to be different, ISO 8601 dates like "2017-01-20" are treated as UTC).
To obtain a date as if the string was parsed as UTC, parse it as local then subtract the timezone offset. ECMAScript timezones have the opposite sense to ISO 8601: east is -ve and west is +ve.
Note that Date objects are just a time value, they get the timezone offset from the host. The following manipulates the time value, nothing else (i.e. it doesn't "set" the timezone in any respsect).
e.g.
/* Parse a date in format August 26,2015 as local
** @param {string} s - string to parse in MMMM DD, YYYY format
** @returns {Date}
*/
function parseMdy(s) {
var months = 'jan feb mar apr may jun jul aug sep oct nov dec'.split(' ');
var b = s.split(/\W/);
var month = months.indexOf(b[0].toLowerCase().substr(0,3));
return new Date(b[2], month, b[1]);
}
// Parse as local
var d = parseMdy('August 26,2015');
console.log('Local date time : ' + d.toString());
// Subtract timezone
d.setMinutes(d.getMinutes() - d.getTimezoneOffset());
console.log('Adjusted to +0000: ' + d.toISOString());
console.log('UNIX time value : ' + (d/1000|0));
Due to the quirky specification for ECMAScript parsing, if the date is formatted per ISO 8601 then the built–in parser will treat it as UTC (but this is still somewhat unreliable):
// August 26,2015 formatted as 2015-08-26
var d = new Date('2015-08-26');
console.log(d.toISOString());
console.log(d/1000|0);
