I have got the same approach but I divided every action in a different line. This way more readable for me. I failed to make a sandwich like you did, still need to train.

It is good to have everything in one line. Saves code space. Good job.

Not an issue, note the description.

This is a good solution!
In my opnion it is easier to read,
if the arguement from map is extracted in a function
and the methode calls are in seperate lines.

How is mutating the input a best practice?

Fixed.

Fixed.

I have seen some of the answers simply return 'true'. There should be test cases to check whether an array is being returned.

Very bad you are allowing $DEITY to kill innocent "imaginary puppies"!!! :'(

Was not able to make more tests. Instead I changed the description of the kata.

If there is someone who can contribute to the unit tests that would be great!

There can be multiples, but there must be a pillow on top of a fridge, ie at the same index position in the different arrays. Updated description to reflect

The description is not clear, for example
Testing for wypvnqwznuw,BnxyuuqwnuB
As per the description string1 has 2 fridges and 2nd string also has 2 fridges but also 2 pillows.
Is the requirement
String 1 in Array: should have a fridge
String 2 in Array: should have a pillow

or there is some order/combination that is expected?

oh well sorry, initially when I first tested the random tests were only returning a single string not an array, so that's not a problem anymore.

But also I guess the random tests are now being random by not just expecting one result, I saw someCongratulations, your baby names are compatible! in there. It may be good to have more variety with the random test cases because about 98% of the tests seem to be expecting: Back to the drawing board, your baby names are not compatible. :)

Requires more tests

Thanks Cleop :)