You're solution is almost right, but for the first Light test it failed because it generates the given object :

> groupAnagrams(["rat", "tar", "star"])
[ [ 'rat', 'tar' ], 
  [ 'star' ], 
  undefined ]

The undefined should not be part of the output for the test to succeed.

Cheers

I've fixed the assertSimilarUnsorted to compare lowercase string versions. Thanks for noticing it !

still undefined ? because it's working for me as I speek

still an issue ? because it's working for me as I speek

Thanks a lot for the revision, that was indeed more explicit. I enjoyed it a lot, as usual with your katas ;)

I've learned a lot ! thank you @nklein for this very very good Kata :)

Done! The test cases now rely on a custom assertSimilarUnsorted matcher :)

Glad you like it :)
Good call fir the order, however I'm stuck because there is no Test matcher that would do the job, I will try to add another prototype method to Test.

You sugguest more test cases in the Kata description ?
Or in the solution test cases ?

So right! You owned me on this one.

The only problem is that it's modifying the initial list passed as argument, right ?