通过使用toLocaleTimeString（）显示时间（以毫秒为单位）

Question

I am attempting to show the time using milliseconds. I'm using the toLocaleTimeString since it supports the locale.

 var milliseconds = 10000; var date = new Date(milliseconds); console.log(date.toLocaleTimeString('en',milliseconds)); // expected result - 0:0:10 AM // actual result - 5:30:10 AM 

The result is not what I'm expected. How can get the expected result using toLocaleTimeString

Answer 1

var date = new Date(10000); is in UTC, ie 1970-01-01 00:00:10 UTC

date.toLocaleTimeString('en') output the time in your system timezone, thus gives the difference you found.

One way to fix is to set date variable to system timezone by adding the timezone difference in milliseconds, as the following:

var date = new Date(10000 + new Date().getTimezoneOffset()*60000); ( new Date().getTimezoneOffset() is timezone difference in minutes)

Answer 2

The normal behaviour of the .toLocaleTimeString() method is to display the time in a string representation based on the local time zone of your environment, that's why you got a different result.

And you were passing a wrong argument milliseconds to it in:

date.toLocaleTimeString('en',milliseconds);

Actually the Date.prototype.toLocaleTimeString() method takes an options object as a second argument, where you can specify several options including the timeZone which specifies the desired time zone for the output.

So call it with {"timeZone": "UTC"} to display it in UTC , like this:

date.toLocaleTimeString('en',{"timeZone": "UTC"})

Demo:

 var milliseconds = 10000; var date = new Date(milliseconds); console.log(date.toLocaleTimeString('en',{"timeZone": "UTC"})); // expected result - 0:0:10 AM // actual result - 5:30:10 AM