moment.js不会将具有特定时区的时间戳转换为Unix时间戳

Question

I am using moment.js to convert a bunch of timestamps in it's specific timezone to a unix timestamp like this:

var timestamp = "2015-12-29T09:35:00.000-08:00";
console.log(moment("2015-12-29T09:35:00.000-08:00").unix();
console.log(moment("2015-12-29T09:35:00.000-08:00").tz("America/Los_Angeles").unix();

The console log of both the above statements is for some reason, the same - 1451361900. This unix timestamp which it is logging is in my local timezone and not the one I asked for: "America/Los_Angeles". What am I missing?

Answer 1

A unix timestamp, or Posix, should always be in the UTC (Coordinated Universal Time) format.

Moment is just doing something like

function unix () {
    return Math.floor(+this / 1000);
}

Where it converts the date object to an integer and then converts from milliseconds to seconds.

The starting point is a regular javascript Date object, and the ECMA standard says

Date objects are based on a time value that is the number of milliseconds since 1 January, 1970 UTC.

so date objects are always UTC when converted to the number of milliseconds since 1. January 1970 (epoch), ie you can't set another timezone on a Unix timestamp, both your dates are the same.

Answer 2

The proper way is to use moment-Timezone is this.

console.log(moment("2015-12-29T09:35:00").unix());
console.log(moment.tz("2015-12-29T09:35" , "America/Los_Angeles").unix());

In above your are providing time zone as a string too which is this last part ".000-08:00" and then you are providing another zone, which is incorrect.

Answer 3

As you are trying to find out the unix timestamp for the date " 2015-12-29T09:35:00.000-08:00 ". In this date format timezone value is already present which is " -08:00 ", hence you get the same unix timestamp.

For getting the unix timestamp desired solution, remove the timezone value and use moment-timezone as :

console.log(moment.tz("2013-12-01", "America/Los_Angeles").unix());

For more details check moment-timezone