View Transitions: list of types

[vmpstr]

こんにちは TAG-さん!

I'm requesting a TAG review of View Transitions: list of types.

The View Transitions feature allows developers to create transitions between DOM states. A significant portion of the transition is a declarative set up, followed by a script trigger. This works well for a single type of transition. However, developers have expressed interest to be able to declare multiple transitions in their CSS, and then trigger only one of them from script. The list of types proposal attempts to address this use case.

• Explainer¹ (minimally containing user needs and example code): https://github.com/vmpstr/web-proposals/blob/main/explainers/view-transition-types.md
• Specification URL:
  • https://drafts.csswg.org/css-view-transitions-2/#the-active-view-transition-pseudo
  • https://drafts.csswg.org/css-view-transitions-2/#additions-to-document-api
• Tests: None yet
• User research: N/A
• Security and Privacy self-review²: N/A as there are no additional security implications over View Transitions API. Let me know if you disagree, and I will put together the self-review.
• GitHub repo (if you prefer feedback filed there): https://github.com/w3c/csswg-drafts/issues (css-view-transitions-2 label)
• Primary contacts (and their relationship to the specification):
  • Vladimir Levin (@vmpstr, Google, implementor)
  • Noam Rosenthal (@noamr, Google, spec author)
• Organization(s)/project(s) driving the specification: Google
• Key pieces of existing multi-stakeholder review or discussion of this specification: This has been discussed at CSSWG via https://github.com/w3c/csswg-drafts/issues/8960
• External status/issue trackers for this specification (publicly visible, e.g. Chrome Status): https://chromestatus.com/feature/5089552511533056

Further details:

• [x] I have reviewed the TAG's Web Platform Design Principles
• Relevant time constraints or deadlines: None
• The group where the work on this specification is currently being done: CSSWG
• The group where standardization of this work is intended to be done (if current group is a community group or other incubation venue): CSSWG
• Major unresolved issues with or opposition to this specification: We have not head of opposition, but some bikeshedding on the names remains to be done.

• This work is being funded by: Google

  💬 leave review feedback as a comment in this issue and @-notify @vmpstr @noamr

[LeaVerou]

Hi @vmpstr,

We just took this up on our breakout A today, but we couldn't find a list of use cases in the explainer. There was this issue which is linked, but it was not clear to us whether that is the only use case, or whether there are more. It would also be useful to include any alternatives considered. Please take a look here for more advice on writing effective explainers.

[vmpstr]

Hi @LeaVerou,

Thank you for the feedback. The use-case described in https://github.com/w3c/csswg-drafts/issues/8960 is the same use-case described in the explainer, and is the main use-case for this API addition to the View Transitions feature.

We are also discussing using types for a similar use-case in the cross-document navigation case, where the polyfill is potentially harder to implement. We are early in the discussion of how types can be used in that case though.

I've added alternatives considered section that mentions this as well.