MomentJS - DateTime Kung Fu

dates and timezones

* Browser display of new Date() or moment().toDate() is always local with info of GMT offset (pacific for e.g)
* Anytime format() is called after toDate(), date is converted to local
* date object always hold local time, it is .utc.format() or .tz("...").format() converts the date into that timezone
* to load UTC time, make sure the date format has ended with "Z"

var m = moment(new Date("2015-12-31 12:00:00")) // no Z, so local date
m.format('MMMM Do YYYY, h:mm:ss a');                    --> "December 31st 2015, 12:00:00 pm"
m.utc().format('MMMM Do YYYY, h:mm:ss a');              --> "December 31st 2015, 8:00:00 pm"
m.tz("US/Eastern").format('MMMM Do YYYY, h:mm:ss a');   --> "December 31st 2015, 3:00:00 pm"
m.tz("US/Eastern").toDate();                            --> Thu Dec 31 2015 12:00:00 GMT-0800 (PST)

var m2 = moment("2015-12-31T12:00:00Z"); //has Z, so GMT
m2.format('MMMM Do YYYY, h:mm:ss a');                   --> "December 31st 2015, 4:00:00 am"  // local (pacific)
m2.tz("US/Eastern").format('MMMM Do YYYY, h:mm:ss a');  --> "December 31st 2015, 7:00:00 am"


var m3 = moment.tz("2015-12-31 12:00:00Z", "America/New_York");
m3.format('MMMM Do YYYY, h:mm:ss a');                    --> "December 31st 2015, 12:00:00 pm"  (eastern)
m3.toDate()                                              --> Thu Dec 31 2015 09:00:00 GMT-0800 (PST) //local, pacific
moment(m3.toDate()).format('MMMM Do YYYY, h:mm:ss a');   --> "December 31st 2015, 9:00:00 am"  //local, pacific
moment(m3.toDate()).tz("America/NEW_YORK").format('MMMM Do YYYY, h:mm:ss a'); --> "December 31st 2015, 12:00:00 pm"  //eastern
m3.utc().format('MMMM Do YYYY, h:mm:ss a');              --> "December 31st 2015, 5:00:00 pm" //UTC