Catch AbortError rejections from overlapping toast view transitions

packages/@adobe/react-spectrum/src/toast/ToastContainer.tsx

@@ -41,11 +41,14 @@ export type CloseFunction = () => void;
 
 function wrapInViewTransition(fn: () => void): void {
   if ('startViewTransition' in document) {
-    document
-      .startViewTransition(() => {
-        flushSync(fn);
-      })
-      .ready.catch(() => {});
+    let transition = document.startViewTransition(() => {
+      flushSync(fn);
+    });
+    // Prevents unhandled promise rejections when a transition is
+    // preempted by another (e.g. overlapping toasts).
+    transition.finished.catch(() => {});
+    transition.ready.catch(() => {});
+    transition.updateCallbackDone.catch(() => {});
   } else {
     fn();
   }

starters/docs/src/Toast.tsx

@@ -25,9 +25,14 @@ export const queue = new ToastQueue<MyToastContent>({
   // Wrap state updates in a CSS view transition.
   wrapUpdate(fn) {
     if ('startViewTransition' in document) {
-      document.startViewTransition(() => {
+      let transition = document.startViewTransition(() => {
         flushSync(fn);
       });
+      // Prevents unhandled promise rejections when a transition is
+      // preempted by another (e.g. overlapping toasts).
+      transition.finished.catch(() => {});
+      transition.ready.catch(() => {});
+      transition.updateCallbackDone.catch(() => {});
     } else {
       fn();
     }

starters/tailwind/src/Toast.tsx

@@ -26,9 +26,14 @@ export const queue = new ToastQueue<MyToastContent>({
   // Wrap state updates in a CSS view transition.
   wrapUpdate(fn) {
     if ('startViewTransition' in document) {
-      document.startViewTransition(() => {
+      let transition = document.startViewTransition(() => {
         flushSync(fn);
       });
+      // Prevents unhandled promise rejections when a transition is
+      // preempted by another (e.g. overlapping toasts).
+      transition.finished.catch(() => {});
+      transition.ready.catch(() => {});
+      transition.updateCallbackDone.catch(() => {});
     } else {
       fn();
     }