[adzm]

Won't this lose precision as you near the limits of a double? Or is it using BigInt behind the scenes?

[dolin_ch]

It's just standard JS numbers (IEEE-754 doubles), not BigInt.

The distance is accumulated in millimeters, so even if someone somehow scrolled hundreds of kilometers we'd still be far below the 2^53 integer precision limit.

So precision loss shouldn't realistically happen.