Flutter | firstwhere error reporting

Error code ：

final array = [1, 2, 3];
final a = array.firstWhere((element) => element == 4);
print(a);

Console display ：

Bad state: No element

Are you kidding me? , Without that element, you will directly report an error , It's too fragile .

Never ignore this problem , An error message means that the following code will not be executed , There must be bug.

What will be wrong ？

The official document says ：

If no element satisfies test, the result of invoking the orElse function is returned. If orElse is omitted, it defaults to throwing a StateError.

If no matching element is found , Will execute orElse function , without orElse function , Will throw out StateError.

Solution 1：

Use try catch Capture exception ：

try {
    
  final array = [1, 2, 3];
  int? a = array.firstWhere((element) => element == 4);
  print(a);
} catch (error) {
    
  //  Without that element 
  //  Do the processing 
}

Solution 2：

Pass in orElse Callback , Return directly when there is no specified element null:

final List<int?> array = [1, 2, 3];
int? a = array.firstWhere(
  (element) => element == 4,
  orElse: () => null,
);
print(a);

Console printing null.