Clarify error handling for standalone startTransition (#8648)

* Clarify standalone startTransition error handling * Polish startTransition error handling docs * Describe startTransition differences neutrally * Clarify startTransition callback wording * Remove repeated startTransition caveat * Preserve existing startTransition guidance * Preserve useTransition error guidance * Update src/content/reference/react/useTransition.md Co-authored-by: Sebastian "Sebbie" Silbermann <silbermann.sebastian@gmail.com> * Clarify standalone startTransition error reporting --------- Co-authored-by: Sebastian "Sebbie" Silbermann <silbermann.sebastian@gmail.com>
react-translations-bot · Sep 8, 2026 · Sep 9, 2026 · Sep 10, 2026 · Sep 10, 2026 · Sep 14, 2026
commit 8efce7853d0fc59e615ed1c253799cf1798b8428
diff --git a/src/content/reference/react/startTransition.md b/src/content/reference/react/startTransition.md
@@ -92,7 +92,7 @@ With a Transition, your UI stays responsive in the middle of a re-render. For ex
 
 <Note>
 
-`startTransition` is very similar to [`useTransition`](/reference/react/useTransition), except that it does not provide the `isPending` flag to track whether a Transition is ongoing. You can call `startTransition` when `useTransition` is not available. For example, `startTransition` works outside components, such as from a data library.
+`startTransition` is very similar to [`useTransition`](/reference/react/useTransition), except that it does not provide the `isPending` flag to track whether a Transition is ongoing. The standalone function is also not associated with a component, so if the function passed to it throws an error or returns a rejected Promise, React reports the error with [`reportError`](https://developer.mozilla.org/en-US/docs/Web/API/Window/reportError). You can call `startTransition` when `useTransition` is not available. For example, `startTransition` works outside components, such as from a data library.
 
 [Learn about Transitions and see examples on the `useTransition` page.](/reference/react/useTransition)
 

diff --git a/src/content/reference/react/useTransition.md b/src/content/reference/react/useTransition.md
@@ -1567,7 +1567,7 @@ main {
 
 ### Displaying an error to users with an error boundary {/*displaying-an-error-to-users-with-error-boundary*/}
 
-If a function passed to `startTransition` throws an error, you can display an error to your user with an [error boundary](/reference/react/Component#catching-rendering-errors-with-an-error-boundary). To use an error boundary, wrap the component where you are calling the `useTransition` in an error boundary. Once the function passed to `startTransition` errors, the fallback for the error boundary will be displayed.
+If a function passed to `startTransition` throws an error or returns a rejected Promise, you can display an error to your user with an [error boundary](/reference/react/Component#catching-rendering-errors-with-an-error-boundary). To use an error boundary, wrap the component where you are calling the `useTransition` in an error boundary. Once the function passed to `startTransition` errors, the fallback for the error boundary will be displayed.
 
 <Sandpack>
 
@@ -1738,7 +1738,11 @@ This is a JavaScript limitation due to React losing the scope of the async conte
 
 ### I want to call `useTransition` from outside a component {/*i-want-to-call-usetransition-from-outside-a-component*/}
 
-You can't call `useTransition` outside a component because it's a Hook. In this case, use the standalone [`startTransition`](/reference/react/startTransition) method instead. It works the same way, but it doesn't provide the `isPending` indicator.
+You can't call `useTransition` outside a component because it's a Hook. In this
+case, the standalone [`startTransition`](/reference/react/startTransition)
+function can mark state updates as Transitions. It does not provide the
+`isPending` flag. Because the standalone function is not associated with a
+component, an Error Boundary cannot handle errors from its Transition.
 
 ---
-Original file line number
+Diff line change
@@ Expand Up @@
     <Note>
-    `startTransition` is very similar to [`useTransition`](/reference/react/useTransition), except that it does not provide the `isPending` flag to track whether a Transition is ongoing. You can call `startTransition` when `useTransition` is not available. For example, `startTransition` works outside components, such as from a data library.
+    `startTransition` is very similar to [`useTransition`](/reference/react/useTransition), except that it does not provide the `isPending` flag to track whether a Transition is ongoing. The standalone function is also not associated with a component, so if the function passed to it throws an error or returns a rejected Promise, React reports the error with [`reportError`](https://developer.mozilla.org/en-US/docs/Web/API/Window/reportError). You can call `startTransition` when `useTransition` is not available. For example, `startTransition` works outside components, such as from a data library.
     [Learn about Transitions and see examples on the `useTransition` page.](/reference/react/useTransition)
@@ Expand Down @@