Intersect documentation is outdated

[ricardo-kagawa]

The documentation at http://turfjs.org/docs/#intersect says that intersect returns undefined for empty intersections, but it seems that it now returns an empty Feature instead, since 4.7.1.

I guess that should have been a major version update, since that is a breaking change. It breaks what is explicitly documented (so intersect(a, b) === undefined does not work anymore), and related idioms (like intersect(a, b) || c).

[DenisCarriere]

Agreed, I don't remember the exact reason why this was changed (strangely it was me who made that change fd592c0).

I personally prefer this type of idiom intersects(a, b) || c.

Additionally, the output was change from undefined to null from @stebogit (edit ea9551d)

🤔 ... I would have no issues reverting this change back to null (or undefined) instead of returning a Feature with null geometry.

@stebogit your thoughts?

[DenisCarriere]

This change should also reflect @turf/difference

[stebogit]

@DenisCarriere @ricardo-kagawa I am not a big fan of Feature<null> either. Also, I would say in this case it's more appropriate returning null (which in my understanding means "none") instead of undefined (like "undetermined).
Good job @DenisCarriere!

This change should also reflect @turf/difference

We should definitely update @turf/difference as well 👍

[DenisCarriere]

Both libraries have been published to reflect null returns.