Null-aware operator with Maps

问题:

I had the same problem with lists, now it is Map.

What I would like to do

The following syntax is not Dart, as in it does not compile:

map?[key] ?? otherValue

If my map was not a Map but a List, it would look like Günter pointed out here:

list?.elementAt(index) ?? otherValue

What I am searching for

I understand that map?[key] is not valid syntax and therefore I am searching for something like elementAt, which works for lists, for maps.

map?.valueFor(key) ?? otherValue

valueOf

That does obviously not yet exist. The problem has solutions and valueOf might be a good one as well.

回答1:

This works:

(map ?? const {})[key] ?? otherValue;

Because the key will access an emtpy Map, which will always return null.

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