This recipe shows you how to handle errors comprehensively when working with Futures. The accompanying code
future_errors.dart (inside the bin map in the
future_errors project) illustrates the different possibilities; however, this is not a real project, so it is not meant to be run as is.
When the function that returns a
Future value completes successfully (calls back) signaled in the code by
then, a callback function
handleValue is executed that receives the value returned. If an error condition took place, the callback
handleError handles it. Let's say this function is
getFuture(), with Future as the result and a return value of type T, then this becomes equivalent to the following code:
Future<T> future ...