In this Hasty Treat, Scott and Wes talk about the new Browser CSS Page Transitions API proposal and what features it opens up for developers on the web.

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Show Notes

WICG Shared Element Transitions
00:21 Welcome
01:33 Sponsor: Prismic
02:43 Sponsor: LogRocket
04:18 Browser animations on the web vs native apps
06:15 What is the targeted use case for it?
06:56 Shared Element to Root Transitions
11:14 Entry and Exit
17:33 How to enable this in Chrome
Example Code
Shared Element Transition history
Sarah Drasner’s demo

 async function doTransition() {   let transition = document.createDocumentTransition();      // Specify offered elements. The tag below is used to refer   // to the generated pseudo elemends in script/CSS.   document.querySelector(".old-message").style.pageTransitionTag = "message";      // The start() call triggers an async operation to capture   // snapshots for the offered elements,   await transition.start(async () => {     // This callback is invoked by the browser when the capture     // finishes and the DOM can be switched to the new state.     // No frames are rendered until this callback returns.          // Asynchronously load the new page.     await coolFramework.changeTheDOMToPageB();          // Clear the old message if that element is still in the page     document.querySelector(".old-message").style.pageTransitionTag = "";     // Set new message as the shared element 'message'     document.querySelector(".new-message").style.pageTransitionTag = "message";          // Set up animations using WA-API on the next frame.     requestAnimationFrame(() => {       document.documentElement.animate(keyframes, {       ...animationOptions,       pseudoElement: "::page-transition-container(message)",       });     });          // Note that when this callback finishes, the animations will start with the tagged elements.   }); }

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Browser CSS Page Transitions API aka Shared Element Transitions

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