javascript - AngularJS global Date timezone offset

Question

I'm looking to show dates relative to the users' timezones.

My hope is that Angular has way to globally config the Date filter to do this—having to do this manually on a case-by-case basis feels wrong.

My timestamps are already wrapped in a timestamp() function (simply to multiply by 1000), but I'd prefer not to modify that function if I don't have to.

Edit:

I'm doing this, and it works, but as stated above, I'd like to set this one level higher if possible

$scope.timestamp = function (unix_time) {
    var epoch = (unix_time * 1000);
    var date = new Date();
    var localOffset = (-1) * date.getTimezoneOffset() * 60000;
    var stamp = Math.round(new Date(epoch + localOffset).getTime());
    return stamp;
};

Answer 1

So, thanks to changes in angular 1.4.x this is now trivial. The proper way to handle this would be to create a decorator that alters the built in date filter before it runs. This is trivially easy, and won't have an impact on performance.

This is one I use. It simply adds a DEFAULT_TIMEZONE if no timezone is specified. This has the effect of moving all dates in the app to GMT as long as no other timezone is given.

module.config(['$provide', function($provide) {
     var DEFAULT_TIMEZONE = 'GMT';

     $provide.decorator('dateFilter', ['$delegate', '$injector', function($delegate, $injector) {
       var oldDelegate = $delegate;

       var standardDateFilterInterceptor = function(date, format, timezone) {
         if(angular.isUndefined(timezone)) {
           timezone = DEFAULT_TIMEZONE;
         }
         return oldDelegate.apply(this, [date, format, timezone]);
       };

       return standardDateFilterInterceptor;
     }]);
}]);