Simplify if (x) Some(y) else None?

Question

This common pattern feels a bit verbose:

if (condition) 
  Some(result)
else None

I was thinking of using a function to simplify:

def on[A](cond: Boolean)(f: => A) = if (cond) Some(f) else None

This reduces the top example to:

on (condition) { result }

Does something like this exist already? Or is this overkill?

Answer 1

You could create the Option first and filter on that with your condition:

Option(result).filter(condition)

or if condition is not related to result

Option(result).filter(_ => condition)

Answer 2

Scalaz includes the option function:

import scalaz.syntax.std.boolean._

true.option("foo") // Some("foo")
false.option("bar") // None

Answer 3

Starting Scala 2.13, Option is now provided with the when builder which does just that:

Option.when(condition)(result)

For instance:

Option.when(true)(45)
// Option[Int] = Some(45)
Option.when(false)(45)
// Option[Int] = None

Also note the coupled unless method which does the opposite.

Answer 4

You can use the PartialFunction companion object and condOpt:

PartialFunction.condOpt(condition) {case true => result}

Usage:

 scala> PartialFunction.condOpt(false) {case true => 42}
 res0: Option[Int] = None

 scala> PartialFunction.condOpt(true) {case true => 42}
 res1: Option[Int] = Some(42)