Answer (1) A nullable type by adding a question mark (?) after the type name. For example, a variable _contacts? can contain a value, or it can be null. Answer (2) It is called “Null-aware operators”.
Read moreAnswer (1) A nullable type by adding a question mark (?) after the type name. For example, a variable _contacts? can contain a value, or it can be null. Answer (2) It is called “Null-aware operators”.
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