How do I define a private final field that is initialized using an optional constructor argument with a default value?

Question

Suppose I have this situation:

class Foo {
  final _bar;
  Foo([bar = 'hello']);
}

In Dart, how do I initialize _bar , given that it's private?

Answer 1

You can use the initializer list.

class Foo {
  final _bar;
  Foo([bar = 'hello']) : _bar = bar;
}

The initializer list is run before the constructor body.