What is double question mark in Dart?

Since version 2.3, Dart adds a new operator called spread which uses three dots ( … ) notations. It can be used to extend the elements of a Collection . The examples below show the usage of the notation on List , Set , and Map .

Since version 2.3, Dart adds a new operator called spread which uses three dots ( … ) notations. It can be used to extend the elements of a Collection . The examples below show the usage of the notation on List , Set , and Map .

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’ .

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’ .

This answer is not useful. Show activity on this post. You might have seen the => symbol in Dart code. This arrow syntax is a way to define a function that executes the expression to its right and returns its value . By using fat arrow => the curly brackets needs to be removed.