ViewTransitions waitUntil() method

concepts

1. waitUntil

   Extend a view transition's lifecycle with arbitrary async work. Useful for waiting on images, fetches, or animations that aren't tied to the DOM update.

2. Cancel or Finish

   The defer-with-timeout pattern: wait for an image to decode but skip the transition if it's too slow. Promise.race + skipTransition give you graceful degradation.

3. Extension Recipes

   Four real-world callers of waitUntil() — image decode, fetch, JS animation, timeout race. Each one fires a transition and shows the timing.

4. Loading States

   A simulated SPA with 3 pages: navigating triggers startViewTransition() with an async callback that waits for a configurable fetch delay. A live timeline shows each phase — setup, capturing, waiting, animating, finished.

why it shipped

The ViewTransition automatically constructs a pseudo-element tree to display and animate participating elements in the transition. Per spec, this subtree is constructed when the view transition starts animating and is destroyed when the animations associated with all view transition pseudo-elements are in the finished state (or more precisely in a non-runnin

references

• ChromeStatus entry
• Spec