How could I do that?

# javascript

[redrield]

How could I do that?

[konsoletyper]

You should follow the logic behind these declarations

[konsoletyper]

In particular, there are two react-router classes that are responsible for that:
https://github.com/ReactTraining/react-router/blob/master/packages/react-router-dom/modules/NavLink.js
and https://github.com/ReactTraining/react-router/blob/master/packages/react-router-dom/modules/Link.js

[konsoletyper]

So, you should provide access to activeClassName property

[konsoletyper]

as well as className

[konsoletyper]

See this declarations among stolen ones?

external interface LinkProps : RProps {
    var to: String
}

Add var className: String

[konsoletyper]

And then modify this DSL declaration:

fun RBuilder.routeLink(to: String, handler: RHandler<RProps>) = child(LinkComponent::class) {
    attrs {
        <http://this.to|this.to> = to
    }
    handler()
}

[konsoletyper]

add className: String? = null parameter and pass it to corresponding property in attrs