Prevent raising IgnoredEventCancel when scrolling on mobile device

[sztobar]

Hello, I noticed in the project that I'm working on that there are a pretty high amount of errors raised from markerjs2:

IgnoredEventCancel: intervention: Ignored attempt to cancel a touchmove event with cancelable=false, for example because scrolling is in progress and cannot be interrupted.

This error is raised when browser is emitting touchmove event on the image, the line that's throwing the error is this:

markerjs2/src/MarkerArea.ts

Line 846 in 3a3700a

this.markerImage.addEventListener('touchmove', (ev) => ev.preventDefault());

and the fix is as simple as this:

    this.markerImage.addEventListener('touchmove', (ev) => ev.cancelable && ev.preventDefault());

this isn't anything critical, I can easily filter this error in the monitoring to avoid logging it as something that needs attention, but given that there's a pretty easy fix for it I thought about informing about it. Have a great day.

[ailon]

Hey. This line was introduced as a workaround for a nasty issue that only manifested on iPads with Apple Pencil. I had to borrow actual hardware to even be able to test it. There is (or at least there was) no way to properly emulate the Apple Pencil. So I'm not really comfortable making this change (however insignificant it looks) without being able to test how it affects the only cause it's there at all.