Thanks for your solution! but its still not clear for me where to create this array errorHosts?

Anywhere that is in scope really, I'd usually put them at the top of the file. Just

const errorHosts = ['X', 'Y', 'Z']

. You can even have them in a separate file if it becomes a large list

thanks again! i created a separate as you suggested but i dont know why there is an issue with import

This is webstorm? Try removing the import and then highlighting the red text and letting webstorm import it for you