sealed-classes-abstract.kt

sealed class State {
  abstract val baz: Boolean

  object Loading : State() {
    override val baz
      get() = TODO("not implemented")

    override fun foo(whatever: Boolean) {
      TODO("not implemented")
    }
  }

  class Error(
    val errorCode: ErrorCode,
    override val baz: Boolean
  ) : State() {

    override fun foo(whatever: Boolean) {
      TODO("not implemented")
    }
  }

  abstract fun foo(whatever: Boolean)

  fun bar() = true
}

enum class ErrorCode(val errorCode: Int) {
  FTW(500),
  LOL(404)
}

// private val stateNotCompile = State()  // Sealed types cannot be instantiated !!!

private val state = Loading               // https://www.youtube.com/watch?v=Ty-IJ3qz-GE :)