Snap Events

[DavMila]

Request for Mozilla Position on an Emerging Web Specification

• Specification title: Snap Events
• Specification or proposal URL (if available): https://drafts.csswg.org/css-scroll-snap-2/#snap-events
• Explainer URL (if available): Snapchanged: https://github.com/argyleink/ScrollSnapExplainers/tree/main/js-snapChanged
  Snapchanging: https://github.com/argyleink/ScrollSnapExplainers/tree/main/js-snapChanging

[emilio]

cc @hiikezoe. I think generally this is fine, the integration looks very similar to scroll events.

[hiikezoe]

Yeah, the basic idea is pretty reasonable to me. Though I don't quite understand why SnapEvent can have only one snapTargetBlock and snapTargetInline on each axis respectively. I suppose it should be a List of nodes. Anyways it should be discussed in CSSWG not here.

[flackr]

Yeah, the basic idea is pretty reasonable to me. Though I don't quite understand why SnapEvent can have only one snapTargetBlock and snapTargetInline on each axis respectively. I support it should be a List of nodes. Anyways it should be discussed in CSSWG not here.

This was in fact was discussed in the CSSWG in w3c/csswg-drafts#9622

The TLDR is that when following an element after a change in layout browsers must have chosen some element to follow per https://drafts.csswg.org/css-scroll-snap-1/#re-snap so we have standarized in that issue how to choose which element is chosen (when multiple are aligned) and are exposing that chosen element in the event.

[hiikezoe]

Thanks for the pointer! I haven't followed the spec issue yet indeed. :)