It’s not that deep onye, it’s not a bug even remotely. It just happens that the developer didn’t calculate delta time either.
This is more of a framework than an engine, which means that the programmer has more freedom, and therefore the “engine” is more to help you with drawing to screen and reading inputs. It doesn’t provide you with an update function or any other kind of structure.
It’s nice you’re trying to help but it’s not that deep. This is all we had to do:
var lastUpdate = Date.now();
var myInterval = setInterval(tick, 0);
function tick() {
var now = Date.now();
var dt = now - lastUpdate;
lastUpdate = now;
}











