getExpirationDate method
get Expiration date in DateTime format.
Implementation
DateTime? getExpirationDate() {
if (expirationDate == null) {
return null;
}
var magic = num.tryParse(expirationDate.toString().substring(0, 14));
if (magic == null) {
return null;
}
// 11644499200000 is the count of millis from DateTime(1601,1,1) -> DateTime(1970,1,1)
// more docs: https://docs.microsoft.com/en-us/uwp/cpp-ref-for-winrt/clock
// https://docs.microsoft.com/en-us/uwp/api/windows.foundation.datetime?view=winrt-22621#remarks
// https://docs.microsoft.com/en-us/uwp/api/windows.services.store.storelicense.expirationdate?view=winrt-22621
magic = magic - 11644499200000;
return DateTime.fromMillisecondsSinceEpoch(magic.toInt());
}