Dart guard

double question mark operator means “if null “. Take the following expression, for example. String a = b ?? ‘hello’; This means a equals b , but if b is null then a equals ‘hello’ .

Show activity on this post. Just create a library file and create fields for globals you need there. Import this library everywhere you need access to these fields. create a singleton in the globals library (see How do you build a Singleton in Dart? for more details).

Dart objects have runtimeType property which returns Type . To check whether the object has a certain type, use == operator . Unlike is , it will only return true if compared to an exectly same type, which means comparing it with its super class will return false .