AngularJS global Date timezone offset

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;
};