Dart optional parameter defaults?

Question

I know that you can do this for things like Strings, ints, but I am wondering if you can set default values ​​for more complex data types like Maps. I tried with a new keyword and several other ways, but they all throw errors.

Answer 1

The default parameters must be constants. You must define your default values ​​using the keyword const.

m([p1 = const['a', 'b']]) => null;

Answer 2

The default values ​​must be constants.

someFunc({someParam: const {'a': 'b'} }) => someParam;