Just compute the colors at each step ;)

Try read Kata "Traffic Light Rules" description again. There is no such transition as O->G

look at the very first test (the description is absolutely bad, actually)

(woops)

done. But don't forget to tell about the language, when you raise an issue.

https://github.com/codewars/codewars.com/wiki/Troubleshooting-your-solution

Just tested javascript (mention the language when reporting an issue) and works fine, the error points to a problem in your code, that we can't see.

Which language?

you must have altered / replaced the expected function name. the kata tests are calling the function anchorize, so you must have your function name be exactly that