What does tripple points means in flutter?-CodePudding

What does ... means in this code?

the code is:

  if (state.isSubmitting) ...[
                const SizedBox(height: 8),
                const LinearProgressIndicator(value: null),
              ]

CodePudding user response：

In Dart (...) Tripple dot is called as spread operator which is basically introduced in Dart 2.3.

Well, spread operator provides an easy way to insert multiple-element into a collection


var numbers = [1, 2, 3];
var numbers2 = [0, ...list];
print(numbers2);

And the spread operator is also a null aware one, for example


var numbers;
var numbers2 = [0, ...?list];
print(numbers2);

for more and conscious explanation you can refer to this link Dart spread operstor

CodePudding user response：

According to Dart documentation, the Spread Operator(...) provides a concise way to insert multiple values into a collection. For instance, let's say there is a List:

var list = [1, 2, 3];

and you want to add this list to another list, you use spread operator

var anotherList = [0, 1, ...list];