Event stream navbar

Navbar.scala

import mhtml._
import scala.xml.Node

class Navbar {
  sealed trait Event
  object Events {
    case object Noop extends Event
    case object Open extends Event
    case object Close extends Event
    case object Toggle extends Event
  }

  case class State(
    open: Boolean = false
  )

  val varEvents = Var(Events.Noop: Event)

  val rxState = varEvents.foldp(State()) {
    case (state, Events.Noop) =>
      state
    case (state, Events.Open) =>
      state.copy(open = true)
    case (state, Events.Close) =>
      state.copy(open = false)
    case (state, Events.Toggle)  =>
      state.copy(open = !state.open)
  }

  val rxOpenStyle = rxState.map(_.open).dropRepeats.map(if (_) "content" else "content show")

  def view: Node = {
    <nav>
      <a class="brand">Brand</a>
      <button class="navbar-toggler" type="button" onclick={ () => varEvents := Events.Toggle }>
        <span></span>
      </button>

      <div class={ rxOpenStyle } >
        <ul>
          <li>
            <a>Home</a>
          </li>
        </ul>
      </div>
    </nav>
  }
}