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I had the same problem with lists, now it is Map.
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 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 That does obviously not yet exist. The problem has solutions and valueOf might be a good one as well.
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In Dart, you can check if a given map is empty or not in several ways. The most convenient approaches are to use the isEmpty, isNotEmpty, or length properties.
Null-aware operators are used in almost every programming language to check whether the given variable value is Null. The keyword for Null in the programming language Dart is null. Null means a variable which has no values assign ever and the variable is initialized with nothing like.
Null-aware operators in Dart help resolve this issue. They're operators to say, "If this object or value is null , then forget about it: stop trying to execute this code." The number-one rule of writing Dart code is to be concise but not pithy.
September 28, 2021. Null safety means that a variable cannot have a null or void value. This feature improves user satisfaction by reducing errors and app crashes. Null safety ensures that all runtime null-dereference problems are shown at compile-time.
This works:
(map ?? const {})[key] ?? otherValue; Because the key will fallback to accessing an empty Map, which will always return null.
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