Futures, then, catchError, whenComplete

A Future represents a value or an error that will be available in the future. This generic class should be used whenever you’re working with time-consuming functions returning a result after a notable amount of time.

int milk = 0;

String? createDrink() {

if (milk == 0) {

throw Exception ("out of milk");

}

if (milk > 4) {

milk = milk - 4;

return 'Cappicino';

}

Future <String?> fetchUserOrder() => Future.delayed(

Duration(seconds:2),

() => createDrink()

);

void main() {

fetchUserOrder().then((result) => print(result))

.catchError((error) => print(error))

.whenComplete(() => print('Done!'));