Underscore: 1.9.0 regression. Calling first or last on an empty array returns undefined.

[ksullivan]

With 1.9.0 _.first([], 10) returns undefined instead of [].

I think this is a big problem :stuck_out_tongue:

[ksullivan]

Wow... It almost looks like this was an intended change... https://github.com/jashkenas/underscore/pull/2513

Personally, I think you would expect _.first([], 2) to be [] following from _.first([1,2,3], 2) being [1,2]

[jashkenas]

That does look like a nasty little regression to me — when called with the number of items specified explicitly. Any other opinions? @jridgewell?

That said, it does raise the question of what _.first([], 1) should be.

[jridgewell]

Whoops, poor review on my part. Passing in a n argument should always return an array.

[jashkenas]

No worries, we can do a 1.9.1 with any other cleanups that arise — plus maybe settling some of the other open PRs...

[lubelski]

gracias. this one bit us too today.

[andreialecu]

This one leads to very obscure bugs in edge cases in lots of various places in a bigger app in my case.

Should it not be a priority?

[tgolen]

This one also bit us. Luckily it was caught by some unit tests before we rolled it out live. I'd be grateful for a quick fix.

[jashkenas]

Alright! Underscore 1.9.1 is now published, with this bugfix in it.

[captbaritone]

Thanks @jashkenas