Nullability of types is an important part of Dart’s type system. In order to simplify the work with nullable types in the Dart language there are
many null-aware operators (??, ??=, ?., !, ?.., ?[], ...?).
Using those operators will make your code more clear and concise.
The If-null operator (??), will check if the value on the left side is null, and, if yes, will return the expression on
the right. This is an easy way to set default values instead of dealing with null. Thus, this operator doesn’t make sense if used with
null on either sides.
For example, in null ?? x the x will always be returned. Using the operator here only introduces confusion and additional
cognitive load. In case of x ?? null, again the result will always be the value of x. In both cases the operator can be
replaced with just x.
