Safe way to access List index - dart

Question

I'm newbee to Dart.
I have troubles to find an easy to read way to "safely" access a List element at any index
final List<String> myList = <String>[]
myList.add("something")
// ...
String myGetter(int index) {
// "heavy" way
if (index < myList.length) {
return myList[index]
}
return null;
}
If I go with regular [index] or elementAt(index) and index is out of boundaries, it throws a RandeError
Is there a method that returns null when the index cannot be reached?
Sorry if double posted, but I try to find the info without any success, + not sure if there is an (un)official slack / discord to ask this kind of "easy" questions

Answer 1

Dart lists do not allow invalid indices. There is no built-in way to get a null when trying. Not in the platform libraries.
You can create your own helper function (like you already do):
T? tryGet<T>(List<T> list, int index) =>
index < 0 || index >= list.length ? null : list[index];
(Remember to check for negative indices too).
As suggested, you can also add it as an extension method:
extension ListGetExtension<T> on List<T> {
T? tryGet(int index) =>
index < 0 || index >= this.length ? null : this[index];
}
which may make it more pleasant to work with.
(I recommend against doing something bad and then catching the error, at least when you can easily check up-front whether it's bad or not).

Answer 2

You can defined an extension method to catch the RangeError and return null:
void main() {
print([1, 2].get(3)); // display null
}
extension SafeLookup<E> on List<E> {
E get(int index) {
try {
return this[index];
} on RangeError {
return null;
}
}
}

Answer 3

You can try this
void main() {
List<int> teste = [1, 2, 3, 4];
print(teste.get(1));
}
extension ListExtension<E> on List<E> {
dynamic get(int value) {
return this.contains(value) ? value : null;
}
}

Answer 4

According to the documentation:
throws a RangeError if index is out of bounds.
So you can use the try-catch block:
String myGetter(int index) {
try {
return myList[index];
}
on RangeError {
// Called when the index is out of bounds
return null;
}
}
If you want to be extra cautious I guess you could put a generic catch at the end (to catch all kinds of throws that are not RangeError), but in a simple getter like this I think that would not be necessary:
[...]
}catch (e) {
// No specified type, handles all other types of error/exceptions
return null;
}
[...]