It is shocking how fast javascript is.

Hyperscript is an interpreted programming language written on top of javascript with an insane runtime that resolves promises at the expression level to implement async transparency.

Head to the playground and select the "Drag" example:

https://hyperscript.org/playground/

And drag that div around. That whole thing is happening in an interpreted event-driven loop:

  repeat until event pointerup from document
    wait for pointermove(pageX, pageY) or
             pointerup(pageX, pageY) from document
    add { left: `${pageX - xoff}`, top: `${pageY - yoff}` }
  end

The fact that the performance of this demo isn't absolutely CPU-meltingly bad is dramatic testament to how smoking fast javascript is.