Convert date to UTC using moment.js

问题:

Probably and easy answer to this but I can't seem to find a way to get moment.js to return a UTC date time in milliseconds. Here is what I am doing:

var date = $("#txt-date").val(),
    expires = moment.utc(date);

Any idea what I am doing wrong?

回答1:

This is found in the documentation. With a library like moment, I urge you to read the entirety of the documentation. It's really important.

Assuming the input text is entered in terms of the users's local time:

 var expires = moment(date).valueOf();

If the user is instructed actually enter a UTC date/time, then:

 var expires = moment.utc(date).valueOf();

回答2:

I use this method and works. ValueOf not works to me.

moment.utc(yourDate).format()

回答3:

If all else fails, just reinitialize with an inverse of your local offset.

var timestamp = new Date();
var inverseOffset = moment(timestamp).utcOffset() * -1;
timestamp = moment().utcOffset( inverseOffset  );

timestamp.toISOString(); // This should give you the accurate UTC equivalent.

回答4:

moment.utc(date).format(...); 

is the way to go, since

moment().utc(date).format(...);

does behave weird...

回答5:

Don't you need something to compare and then retrieve the milliseconds?

For instance:

let enteredDate = $("#txt-date").val(); // get the date entered in the input
let expires = moment.utc(enteredDate); // convert it into UTC

With that you have the expiring date in UTC. Now you can get the "right-now" date in UTC and compare:

var rightNowUTC = moment.utc(); // get this moment in UTC based on browser
let duration = moment.duration(rightNowUTC.diff(expires)); // get the diff
let remainingTimeInMls = duration.asMilliseconds();