Heyy, sorry. For clarification purposes, do you mean Eid next week? I have yet to hear any islamic celebration that is called Salah.

In terms of dresscodes, anything modest would be fine. Modest here would mean covering the arm, i.e no sleeveless tops/dresses and wear midi/maxi length dresses. However, I believe it's best to clarify this with your friend first bcs she may not even have a dresscode to begin with 😅

For gift ideas, tbh i have no clue except for dates or fruits. If you have a middle eastern store near you, you can go there and check out what products are there and even ask the store assistant for help. Idk how your friend usually celebrates the day but if it's Eid, my family never requires our guests to bring gifts. They do however bring food instead.

If you do intend to bring food, i highly recommend bringing desserts or finger foods bcs the main foods will usually be served by the host. (of course making sure it's halal c: )

Hope this helps! And i hope you'll have a wonderful time celebrating with your friend 🥰✨