Is the first class citizen.
Is not supported.
There's nothing fundamental about why it couldn't be cross compiled for scala 2 and I have nothing against it, this is a personal project on personal time.
See here! One of the explicit goals of this library is to be able to cross compile the same chart you figured out in the repl, to scala JS.
I have not thought of a need for this yet. In theory it would work trivially as it's all built out of sbt typelevel.