Adding power outlets in slide with no wiring

I am looking at adding a 12V circuit into my slide so we have overhead lights where there currently are none.  I've considered a rechargeable LED light that I could hang but looking at something more permanent that will look nice.

My question is how do they run power such that the cord extends with the slide but isn't hanging down to the ground when the slide is retracted?   Again, there is ZERO power currently run to the slide, AC nor DC.  I am a former electrician turned electrical engineer turned electrical apprentice trainer so am.no stranger to wiring.  I've got that side handled, I think.

TIA