Document extending JavaScript interfaces

[ohde]

I believe after https://github.com/scala-js/scala-js-website/blob/master/doc/calling-javascript.md#defining-javascript-interfaces-with-traits it would be beneficial to show extending a Javascript interface. That way users can easily see how to enrich their JavaScript APIs with minimal work. I have provided an example below. However, I am sure a more useful example can be provided.

trait Window extends js.Object { 
  def alert(message: String): Unit = js.native
} 
object Window {
  implicit class RichWindow(val self: Window) extends AnyVal {
    def help: Unit = self.alert("help")
  }
}

[sjrd]

Yes, it's probably worth documenting it. Although it's a fairly common general Scala idiom.

[ohde]

Yes, I agree with you. But it might be worth at least putting in an aside for people experimenting with scalajs who are not that familiar with Scala.

[ochrons]

This is now documented in http://www.scala-js.org/doc/interoperability/facade-types.html

[sjrd]

Is it? Searching implicit class does not yield any result.

[ochrons]

Ah, you are right, didn't look closely enough :)