DART

What is Dart?

Dart is a general-purpose, object-oriented programming language with C-style syntax.

what means ?? in dart

// The ?? double question mark operator means "if null"
String a = b ?? 'hello'; // This means a equals b, but if b is null then a equals 'hello'. It is like || in JavaScript

b ??= 'hello'; // If b is null then set it equal to 'hello'. Otherwise, don't change it