From 8d48673e3540869bb1ae989f2a95931624a36cec Mon Sep 17 00:00:00 2001
From: Sebastian Markbage <sebastian@calyptus.eu>
Date: Mon, 6 Jan 2025 13:04:40 -0500
Subject: [PATCH] Only support View Transitions v2

---
 .../src/client/ReactFiberConfigDOM.js         | 31 ++++++++++++-------
 1 file changed, 20 insertions(+), 11 deletions(-)

diff --git a/packages/react-dom-bindings/src/client/ReactFiberConfigDOM.js b/packages/react-dom-bindings/src/client/ReactFiberConfigDOM.js
index dbb552a63f7..f957b527699 100644
--- a/packages/react-dom-bindings/src/client/ReactFiberConfigDOM.js
+++ b/packages/react-dom-bindings/src/client/ReactFiberConfigDOM.js
@@ -1187,19 +1187,28 @@ export function startViewTransition(
     rootContainer.nodeType === DOCUMENT_NODE
       ? rootContainer
       : rootContainer.ownerDocument;
-  // $FlowFixMe[prop-missing]
-  if (typeof ownerDocument.startViewTransition !== 'function') {
+  try {
+    // $FlowFixMe[prop-missing]
+    const transition = ownerDocument.startViewTransition({
+      update() {
+        mutationCallback();
+        // TODO: Wait for fonts.
+        afterMutationCallback();
+      },
+      types: null, // TODO: Provide types.
+    });
+    transition.ready.then(layoutCallback, layoutCallback);
+    transition.finished.then(passiveCallback);
+    return true;
+  } catch (x) {
+    // We use the error as feature detection.
+    // The only thing that should throw is if startViewTransition is missing
+    // or if it doesn't accept the object form. Other errors are async.
+    // I.e. it's before the View Transitions v2 spec. We only support View
+    // Transitions v2 otherwise we fallback to not animating to ensure that
+    // we're not animating with the wrong animation mapped.
     return false;
   }
-  // $FlowFixMe[incompatible-use]
-  const transition = ownerDocument.startViewTransition(() => {
-    mutationCallback();
-    // TODO: Wait for fonts.
-    afterMutationCallback();
-  });
-  transition.ready.then(layoutCallback, layoutCallback);
-  transition.finished.then(passiveCallback);
-  return true;
 }
 
 export function clearContainer(container: Container): void {