WoW LUA - cache issue

[loff93]

Hello!

Just started working with lua and WoW addons. It's pretty fun and I have already made some simple addons.
My only issue so far is the cache. When the items I try to use is not in the local cache and I end up getting errors. How can I manage to get the item info right away, to avoid GetItemInfo(id) being equal to "nil" unless I already have it in cache?
I'm pretty new to lua even if I have worked with programming so try to explain it in a simple way if possible.

Thanks!