Get UnitId of UnitIds target

[vectros]

Hello,

I am developing my own addon and I came to a place where I encountered the following problem:

1. I have NPC's UnitID
2. I want to compare that UnitIDs TARGET with player for example.
3. if UnitIsUnit(unitID-target, "player") then doesn't work unfortunately (I've tried all combinations of that).

Is there any way to achieve that?

Seems like there's no way to compare UnitID variable with some selector ("target", "player" etc). Am I right?

Thanks