i would suggest to try to reverse the way you get to seconds from a year

Please don't spoil solutions. Users are not supposed to find solutions to the kata on the discourse page...

names[names.length - 2] will return the index of the array.

try creating a variable with the length of the array, them u can subtract

You only can unlock solutions of katas 1 level above your current level, reach lvl 5 and try again later.

well, you never declared any length variable :p

Read this: https://docs.codewars.com/getting-started/solving-kata

After successfully passing the tests when clicking Attempt button, it changes to Submit. Click that button again to see other solutions.

You should ask such questions in the solutions section. (once you submit your solution)

And it won't work until you see Node v15+ enabled in the site: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/replaceAll#browser_compatibility

Find another way, without using replaceAll

If you want to undo what you did with split, use the same argument with join. Read the docs, they're made so you know how to use those methods.

I already gave you a suggestion, I won't tell you replace X for Y, that's your job. Read the second link I posted, you're using join wrong, and that's the reason you needed replaceAll in the first place.

The link is a general how to for troubleshooting your solution.

Don't use replaceAll, you don't need it at all. Read in MDN about the methods you use to see how to use them: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array

Not a kata suggestion, please read this: https://docs.codewars.com/training/troubleshooting

About replaceAll it's not available in all Node's versions. Please mark your post as having spoiler content next time.