Set a limit to scala.rx timer - scala

Question

Here is an example using Timer from scala.rx:
package tutorial.webapp
import akka.actor.ActorSystem
import rx.core.{Rx, Var}
import rx._
import rx.ops._
import scala.concurrent.Promise
import scala.concurrent.duration._
import scala.scalajs.js.JSApp
import scala.scalajs.js.annotation.JSExport
import scala.concurrent.ExecutionContext.Implicits.global
/**
* Created by IDEA on 29/10/15.
*/
object RxAddtionalOps extends JSApp {
#JSExport
override def main(): Unit = {
timer1
}
def timer1: Unit = {
implicit val scheduler = new DomScheduler
val t = Timer(100 millis)
var count = 0
val o = Obs(t){
count = count + 1
println(count)
}
}
}
When you run runMain tutorial.webapp.RxAddtionalOps from sbt, the console will be indefinitely blocked. Can I set a limit to the timer? For example, to make it stop emitting events in 2 minutes.

Answer 1

First of all, Scala is a language for express common programming patterns in a concise, elegant, and type-safe way. So keep your work tidy!
Therefore
import akka.actor.ActorSystem
import rx.core.{Rx, Var}
import rx._
import scala.concurrent.Promise
is a lot of unnecessary noise. And if the target is a JavaScript platform, the Actor system is not available yet, maybe over couple of years.
Why should you fire runMain tutorial.webapp.RxAddtionalOps in sbt, while a simple run command will do?
I used the Timer.kill() method to terminate the execution after a limited time:
package tutorial.webapp
import rx.Obs
import rx.ops.{DomScheduler, Timer}
import scala.concurrent.ExecutionContext.Implicits.global
import scala.concurrent.duration._
import scala.language.postfixOps
import scala.scalajs.js.JSApp
object RxAddtionalOps extends JSApp {
val executionStart = scala.compat.Platform.currentTime
def main(): Unit = {
timer1()
}
def timer1() = {
implicit val scheduler = new DomScheduler
val t = Timer(100 millis)
var count = 0
Obs(t) {
count += 1
println(count)
if (count >= 19) {
t.kill()
println(s"Successfully completed without errors. [within ${
scala.compat.Platform.currentTime - executionStart
} ms]")
}
}
}
}
Since it is actually a headless phantom or rhino environment (depending on your build.sbt config) there can be no user initiated interrupt processed.
For completeness here the build.sbt file:
name := "RxAddtionalOps"
version := "1.0"
scalaVersion := "2.11.7"
enablePlugins(ScalaJSPlugin)
scalacOptions ++= Seq("-unchecked", "-deprecation","-feature")
libraryDependencies ++= Seq(
"com.lihaoyi" %%% "scalarx" % "0.2.8",
"org.scala-js" %% "scalajs-library" % "0.6.5"
)