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. }); } Tweet us your tasty treats

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