In Example at https://pub.dev/packages/contacts_service/versions/0.4.3/example there is a code like as follows
itemCount: _contacts?.length ?? 0,
and I have two question on that,
what is meant by variableName? ( variableName followed by question mark '?') e.g in above _contacts?
The second question was on two question marks and is at What are the ?? double question marks in Dart?
Solution 1: Jay Kukadiya
"Variable?" is use for null safety. If _contact has value null then we can't check length of variable or it's throw error.
"??" is used for if condition. It's assign value 0.
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