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Not an issue

For better task understanding you could make better code quality/readability with some meaningful function names instead of just anonymous functions.
Without doing final attempt to task, there is hard to understand that code need to handle integer convertation to octal number too.

I think it's too easy. For begginers there need just to find only one javascript method to complete this kata.

I think this kata is too easy, need much more decription and harder task.