Questions about `DomUtil.preventDefault()`

[danallsop]

Migrated from: Leaflet#9934
Original author: danallsop
Original created: 2025-10-07T22:20:02Z

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So what I am confused about is why we are passing things that are not Event to this function in the first place. The test failures in Leaflet#9894 (comment) seem to indicate a larger issue that raises questions for me:

1. Should we have been calling .preventDefault() on originalEvent if present? (e.g. we do have some special handling for stopping events
2. Why does this originalEvent even exist in the first place? Could we possibly get rid of it?
3. Is it even the responsibility of DomUtil.preventDefault() to check for the existence of preventDefault(), or should it have never been called in the first place? (perhaps this should have been handled in DomEvent.stop()?)

danallsop/core danallsop/leaflet-maintainers any insights into this?

Either way, I am approving this PR as this discussion is out of scope for what is being delivered here, so feel free to merge. I would still like to get some answers.

Originally posted by danallsop in Leaflet#9894 (comment)

[danallsop]

Comments (1 total)

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Comment by: danallsop on 2025-10-07T22:50:42Z

danallsop IIRC, the IE8 era was difficult due to event handling. One couldn't be sure if the right thing to do was to stop event propagation or preventing the default, or both. Heck, we didn't have the defaultPrevented property back then.

About originalEvent - we're still doing weird stuff to trigger context menus (i.e. "right click") on holding the pointer on iOS, and double clicking. Unless we can get rid of all those hacks, I'd leave originalEvent as is.