Node v6.0.0 was just released and has a long list of breaking changes - this means that not all packages are ready to run on Node v6.0.0, even though it’s the stable/current build right now.
This is also the case with node-sass
used by Ionic (which causes problems like this or this):
xzyfer: Node 6 is not yet supported. This will be case for many native extensions like filesystem watchers. Generally speaking don’t expect everything to work when you’re using the bleeding edge.
That’s why I would recommend you to NOT rush to upgrade to Node v6 right away.