gistfile1.scala

case class Props(color: String, onClick: Unit => Unit)

class Backend($: BackendScope[Props, _]) {
  def onClick(e: ReactEventI) = {
    println("clicked!")
    $.props.onClick()
}

val circ = ReactComponentB[Props]("CircleComponent")
  .stateless
  .backend(new Backend(_))
  .render((props, _, b) =>
    div(
      svg(width := 800, height := 100,
        g(transform := "translate(100, 0)",
          onKeyPress ==> b.onClick,
          circle(
            cx := "25", cy := "25", r := "25", fill := props.color)
        )
      )
    )
  )
  .build