Future< T>.sync constructor
Returns a future containing the result of immediately calling
computation
.
If calling computation
throws, the returned future is completed with the
error.
If calling computation
returns a Future<T>
, that future is returned.
If calling computation
returns a non-future value,
a future is returned which has been completed with that value.
Implementation
factory Future.sync(FutureOr<T> computation()) {
try {
var result = computation();
if (result is Future<T>) {
return result;
} else if (result is Future) {
// TODO(lrn): Remove this case for Dart 2.0.
return new _Future<T>.immediate(result);
} else {
return new _Future<T>.value(result);
}
} catch (error, stackTrace) {
var future = new _Future<T>();
AsyncError replacement = Zone.current.errorCallback(error, stackTrace);
if (replacement != null) {
future._asyncCompleteError(
_nonNullError(replacement.error), replacement.stackTrace);
} else {
future._asyncCompleteError(error, stackTrace);
}
return future;
}
}