The worst solution is to mutate the original data.

unpowerful

I don't like this solution because you are mutating the function argument.

I don't like this solution because you are mutating the function argument.

very bad for JS, dislike

two loops

I refuse to solve this kata, it's terrible

Example: the teacher gave the task to find a favorite quote from the Harry Potter book and show it to the whole class.

Solutions without mutation: copy the quote from the book with chalk onto the school board, scan the book page, print the quote from the electronic version of the book and stick it on the board.

Solution with mutation: take scissors, cut out the quote from the book and stick it on the board.

Mutating an argument is the worst thing you can do.

Mutating an argument is the worst thing you can do.

Mutating an argument is the worst thing you can do.

The whole difficulty of the kata lies in its poor explanation.

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cool kata

Too easy kata, maybe it's level 7