Your question is What is an IIFE and When Is It Useful. Take a moment with it on the right.
Talk me through your thinking if you like. When you're confident, submit your answer and I'll grade it like a real screen (7/10 or better passes).
Tell me about what an IIFE (Immediately Invoked Function Expression) is and when you would find it useful in a production JavaScript codebase at Once For All.