"natural order" is that means "dictionary order"?
like "abcd" < "accd" , the first diff-letter "b" < "c"

after solve it, my guess is right~

^_^ Nice kata to practice emmmmm~， can't say here~

( JS )

• Your solution must pass in lss than ref.solution-10ms speed.

That's actually + 10 ms. ( Also, "less" :P )

You can see (and discuss) your or other's solutions in Solutions. Make sure you mark your posts as having spoiler content there when needed too. Kata discourse is a place to ask for help, suggest improvements and report issues (and make some comments too), but not to post your own solution.
Note that posting something in Solutions is totally optional, you don't need to post anything there at all. Other coding sites work differently, but here, your code passes the tests and you're awarded with honor points for it or it doesn't pass and you don't get any points. You can also get honor points for other things, read this: https://github.com/Codewars/codewars.com/wiki/Kata-Solutions-&-Voting

The array is already sorted!!!!!

Ok, i didn't know that I cannot do it here.
Where can I do it?

But sorting an array also requires performance overhead. This is clearly not the case when you need to do extra body movements.

Please, don't post solutions in Discourse.

There is a manner to find the index of a unique item in a sorted array which is way faster than looping through the entire array.

Sorry, but i didn't undersatand you. In task i must be only find default word, right?

• not an issue
• you should read this

not an issue

You must take advantage of the fact that the array is sorted...