Expose Function.option()

[Luis M]

Please make this method public. It's useful for working with collections that may have null elements.

[Jed Wesley-Smith]

I added it but renamed to nullToOption to make it clearer what its point is. I also renamed compose to composeOption and added proper function composition in its place (compose(B => C, A => B): A => C).

Unfortunately this missed 2.2 so will be in 2.3 (unless the above means next release is 3.0)

[Jed Wesley-Smith]

add Functions.nullToOption