This looks good (minus the CI failing, should be easy to fix though)

I wonder if it's also worth adding an example with a version for numbers, given how often that's going to be the code people are looking for?

@orta I'm not sure if it's the most common case to be used as example. If you have numbers or strings, you don't usually use custom compareFn (unless you want them to sort in descending order, but this would be misleading as example). Maybe something like this?

(a, b) => a.index - b.index

Afraid not, wish it were true:

$ node

> [1,2,11,23,3,5].sort()
[ 1, 11, 2, 23, 3, 5 ]

> [1,2,11,23,3,5].sort((lhs, rhs) => lhs - rhs)
[ 1, 2, 3, 5, 11, 23 ]

Because it's alphabetical, not numerical - I've made this mistake a lot!

@orta you're right, of course - and certainly have a point that example is needed

Alright - that's the baselines updated (basically compiler snapshots which got updated because the line references changed) and I've merged master.

Will merge this when it greens. Thanks @m1gu3l :D