From 8bb31acb86bf68fa33d97dd0f1b834dfa71e2b1a Mon Sep 17 00:00:00 2001
From: Jack Pope <jackpope1@gmail.com>
Date: Wed, 17 Jun 2026 10:38:02 -0700
Subject: [PATCH 1/9] Expand FragmentInstance reference docs (#8309)

* Clean up and expand fragment ref docs

* Add cached intersection observer usage example

* Expand focus example to show search

* Small clean ups

* Add FragmentInstance operations reference list

* Add reference to scrollIntoView operation

* Migrate examples to sandpack
---
 src/content/reference/react/Fragment.md | 824 ++++++++++++++++++++++--
 1 file changed, 763 insertions(+), 61 deletions(-)

diff --git a/src/content/reference/react/Fragment.md b/src/content/reference/react/Fragment.md
index 5ffc45277..14a534bbc 100644
--- a/src/content/reference/react/Fragment.md
+++ b/src/content/reference/react/Fragment.md
@@ -6,7 +6,7 @@ title: <Fragment> (<>...</>)
 
 `<Fragment>`, often used via `<>...</>` syntax, lets you group elements without a wrapper node.
 
-<Canary> Fragments can also accept refs, which enable interacting with underlying DOM nodes without adding wrapper elements. See reference and usage below.</Canary>
+<Canary>Fragments can also accept refs, which enable interacting with underlying DOM nodes without adding wrapper elements.</Canary>
 
 ```js
 <>
@@ -30,41 +30,258 @@ Wrap elements in `<Fragment>` to group them together in situations where you nee
 #### Props {/*props*/}
 
 - **optional** `key`: Fragments declared with the explicit `<Fragment>` syntax may have [keys.](/learn/rendering-lists#keeping-list-items-in-order-with-key)
-- <CanaryBadge />  **optional** `ref`: A ref object (e.g. from [`useRef`](/reference/react/useRef)) or [callback function](/reference/react-dom/components/common#ref-callback). React provides a `FragmentInstance` as the ref value that implements methods for interacting with the DOM nodes wrapped by the Fragment.
+- <CanaryBadge /> **optional** `ref`: A ref object (e.g. from [`useRef`](/reference/react/useRef)) or [callback function](/reference/react-dom/components/common#ref-callback). React provides a `FragmentInstance` as the ref value that implements methods for interacting with the DOM nodes wrapped by the Fragment.
 
-### <CanaryBadge /> FragmentInstance {/*fragmentinstance*/}
+#### Caveats {/*caveats*/}
 
-When you pass a ref to a fragment, React provides a `FragmentInstance` object with methods for interacting with the DOM nodes wrapped by the fragment:
+* If you want to pass `key` to a Fragment, you can't use the `<>...</>` syntax. You have to explicitly import `Fragment` from `'react'` and render `<Fragment key={yourKey}>...</Fragment>`.
 
-**Event handling methods:**
-- `addEventListener(type, listener, options?)`: Adds an event listener to all first-level DOM children of the Fragment.
-- `removeEventListener(type, listener, options?)`: Removes an event listener from all first-level DOM children of the Fragment.
-- `dispatchEvent(event)`: Dispatches an event to a virtual child of the Fragment to call any added listeners and can bubble to the DOM parent.
+* React does not [reset state](/learn/preserving-and-resetting-state) when you go from rendering `<><Child /></>` to `[<Child />]` or back, or when you go from rendering `<><Child /></>` to `<Child />` and back. This only works a single level deep: for example, going from `<><><Child /></></>` to `<Child />` resets the state. See the precise semantics [here.](https://gist.github.com/clemmy/b3ef00f9507909429d8aa0d3ee4f986b)
 
-**Layout methods:**
-- `compareDocumentPosition(otherNode)`: Compares the document position of the Fragment with another node.
-  - If the Fragment has children, the native `compareDocumentPosition` value is returned.
-  - Empty Fragments will attempt to compare positioning within the React tree and include `Node.DOCUMENT_POSITION_IMPLEMENTATION_SPECIFIC`.
-  - Elements that have a different relationship in the React tree and DOM tree due to portaling or other insertions are `Node.DOCUMENT_POSITION_IMPLEMENTATION_SPECIFIC`.
-- `getClientRects()`: Returns a flat array of `DOMRect` objects representing the bounding rectangles of all children.
-- `getRootNode()`: Returns the root node containing the Fragment's parent DOM node.
+* <CanaryBadge /> If you want to pass `ref` to a Fragment, you can't use the `<>...</>` syntax. You have to explicitly import `Fragment` from `'react'` and render `<Fragment ref={yourRef}>...</Fragment>`.
 
-**Focus management methods:**
-- `focus(options?)`: Focuses the first focusable DOM node in the Fragment. Focus is attempted on nested children depth-first.
-- `focusLast(options?)`: Focuses the last focusable DOM node in the Fragment. Focus is attempted on nested children depth-first.
-- `blur()`: Removes focus if `document.activeElement` is within the Fragment.
+---
 
-**Observer methods:**
-- `observeUsing(observer)`: Starts observing the Fragment's DOM children with an IntersectionObserver or ResizeObserver.
-- `unobserveUsing(observer)`: Stops observing the Fragment's DOM children with the specified observer.
+### <CanaryBadge /> `FragmentInstance` {/*fragmentinstance*/}
 
-#### Caveats {/*caveats*/}
+When you pass a `ref` to a Fragment, React provides a `FragmentInstance` object. It implements methods for interacting with the first-level DOM children wrapped by the Fragment.
+
+* [`addEventListener`](#addeventlistener) and [`removeEventListener`](#removeeventlistener) manage event listeners across all first-level DOM children.
+* [`dispatchEvent`](#dispatchevent) dispatches an event on the Fragment, which can bubble to the DOM parent.
+* [`focus`](#focus), [`focusLast`](#focuslast), and [`blur`](#blur) manage focus across all nested children depth-first.
+* [`observeUsing`](#observeusing) and [`unobserveUsing`](#unobserveusing) attach and detach `IntersectionObserver` or `ResizeObserver` instances.
+* [`getClientRects`](#getclientrects) returns bounding rectangles of all first-level DOM children.
+* [`getRootNode`](#getrootnode) returns the root node of the Fragment's parent.
+* [`compareDocumentPosition`](#comparedocumentposition) compares the Fragment's position with another node.
+* [`scrollIntoView`](#scrollintoview) scrolls the Fragment's children into view.
+
+---
+
+#### `addEventListener(type, listener, options?)` {/*addeventlistener*/}
+
+Adds an event listener to all first-level DOM children of the Fragment.
+
+```js
+fragmentRef.current.addEventListener('click', handleClick);
+```
+
+##### Parameters {/*addeventlistener-parameters*/}
+
+* `type`: A string representing the event type to listen for (e.g. `'click'`, `'focus'`).
+* `listener`: The event handler function.
+* **optional** `options`: An options object or boolean for capture, matching the [DOM `addEventListener` API.](https://developer.mozilla.org/en-US/docs/Web/API/EventTarget/addEventListener)
+
+##### Returns {/*addeventlistener-returns*/}
+
+`addEventListener` does not return anything (`undefined`).
+
+---
+
+#### `removeEventListener(type, listener, options?)` {/*removeeventlistener*/}
+
+Removes an event listener from all first-level DOM children of the Fragment.
+
+```js
+fragmentRef.current.removeEventListener('click', handleClick);
+```
+
+##### Parameters {/*removeeventlistener-parameters*/}
+
+* `type`: The event type string.
+* `listener`: The event handler function to remove.
+* **optional** `options`: An options object or boolean, matching the [DOM `removeEventListener` API.](https://developer.mozilla.org/en-US/docs/Web/API/EventTarget/removeEventListener)
+
+##### Returns {/*removeeventlistener-returns*/}
+
+`removeEventListener` does not return anything (`undefined`).
+
+---
+
+#### `dispatchEvent(event)` {/*dispatchevent*/}
+
+Dispatches an event on the Fragment. Added event listeners are called, and the event can bubble to the Fragment's DOM parent.
+
+```js
+fragmentRef.current.dispatchEvent(new Event('custom', { bubbles: true }));
+```
+
+##### Parameters {/*dispatchevent-parameters*/}
+
+* `event`: An [`Event`](https://developer.mozilla.org/en-US/docs/Web/API/Event) object to dispatch. If `bubbles` is `true`, the event bubbles to the Fragment's parent DOM node.
+
+##### Returns {/*dispatchevent-returns*/}
+
+`true` if the event was not cancelled, `false` if `preventDefault()` was called.
+
+---
+
+#### `focus(options?)` {/*focus*/}
+
+Focuses the first focusable DOM node in the Fragment. Unlike calling `element.focus()` on a DOM element, this method searches *all* nested children depth-first until it finds a focusable element—not just the element itself or its direct children.
+
+```js
+fragmentRef.current.focus();
+```
+
+##### Parameters {/*focus-parameters*/}
+
+* **optional** `options`: A [`FocusOptions`](https://developer.mozilla.org/en-US/docs/Web/API/HTMLElement/focus#options) object (e.g. `{ preventScroll: true }`).
+
+##### Returns {/*focus-returns*/}
+
+`focus` does not return anything (`undefined`).
+
+---
+
+#### `focusLast(options?)` {/*focuslast*/}
+
+Focuses the last focusable DOM node in the Fragment. Searches nested children depth-first, then iterates in reverse.
+
+```js
+fragmentRef.current.focusLast();
+```
+
+##### Parameters {/*focuslast-parameters*/}
+
+* **optional** `options`: A [`FocusOptions`](https://developer.mozilla.org/en-US/docs/Web/API/HTMLElement/focus#options) object.
+
+##### Returns {/*focuslast-returns*/}
+
+`focusLast` does not return anything (`undefined`).
+
+---
+
+#### `blur()` {/*blur*/}
+
+Removes focus from the active element if it is within the Fragment. If `document.activeElement` is not within the Fragment, `blur` does nothing.
+
+```js
+fragmentRef.current.blur();
+```
+
+##### Returns {/*blur-returns*/}
+
+`blur` does not return anything (`undefined`).
+
+---
+
+#### `observeUsing(observer)` {/*observeusing*/}
+
+Starts observing all first-level DOM children of the Fragment with the provided observer.
+
+```js
+const observer = new IntersectionObserver(callback, options);
+fragmentRef.current.observeUsing(observer);
+```
+
+##### Parameters {/*observeusing-parameters*/}
 
-- If you want to pass `key` to a Fragment, you can't use the `<>...</>` syntax. You have to explicitly import `Fragment` from `'react'` and render `<Fragment key={yourKey}>...</Fragment>`.
+* `observer`: An [`IntersectionObserver`](https://developer.mozilla.org/en-US/docs/Web/API/IntersectionObserver) or [`ResizeObserver`](https://developer.mozilla.org/en-US/docs/Web/API/ResizeObserver) instance.
 
-- React does not [reset state](/learn/preserving-and-resetting-state) when you go from rendering `<><Child /></>` to `[<Child />]` or back, or when you go from rendering `<><Child /></>` to `<Child />` and back. This only works a single level deep: for example, going from `<><><Child /></></>` to `<Child />` resets the state. See the precise semantics [here.](https://gist.github.com/clemmy/b3ef00f9507909429d8aa0d3ee4f986b)
+##### Returns {/*observeusing-returns*/}
 
-- <CanaryBadge /> If you want to pass `ref` to a Fragment, you can't use the `<>...</>` syntax. You have to explicitly import `Fragment` from `'react'` and render `<Fragment ref={yourRef}>...</Fragment>`.
+`observeUsing` does not return anything (`undefined`).
+
+---
+
+#### `unobserveUsing(observer)` {/*unobserveusing*/}
+
+Stops observing the Fragment's DOM children with the specified observer.
+
+```js
+fragmentRef.current.unobserveUsing(observer);
+```
+
+##### Parameters {/*unobserveusing-parameters*/}
+
+* `observer`: The same `IntersectionObserver` or `ResizeObserver` instance previously passed to [`observeUsing`](#observeusing).
+
+##### Returns {/*unobserveusing-returns*/}
+
+`unobserveUsing` does not return anything (`undefined`).
+
+---
+
+#### `getClientRects()` {/*getclientrects*/}
+
+Returns a flat array of [`DOMRect`](https://developer.mozilla.org/en-US/docs/Web/API/DOMRect) objects representing the bounding rectangles of all first-level DOM children.
+
+```js
+const rects = fragmentRef.current.getClientRects();
+```
+
+##### Returns {/*getclientrects-returns*/}
+
+An `Array<DOMRect>` containing the bounding rectangles of all children.
+
+---
+
+#### `getRootNode(options?)` {/*getrootnode*/}
+
+Returns the root node containing the Fragment's parent DOM node, matching the behavior of [`Node.getRootNode()`](https://developer.mozilla.org/en-US/docs/Web/API/Node/getRootNode).
+
+```js
+const root = fragmentRef.current.getRootNode();
+```
+
+##### Parameters {/*getrootnode-parameters*/}
+
+* **optional** `options`: An object with a `composed` boolean property, matching the [DOM `getRootNode` API.](https://developer.mozilla.org/en-US/docs/Web/API/Node/getRootNode#options)
+
+##### Returns {/*getrootnode-returns*/}
+
+A `Document`, `ShadowRoot`, or the `FragmentInstance` itself if there is no parent DOM node.
+
+---
+
+#### `compareDocumentPosition(otherNode)` {/*comparedocumentposition*/}
+
+Compares the document position of the Fragment with another node, returning a bitmask matching the behavior of [`Node.compareDocumentPosition()`](https://developer.mozilla.org/en-US/docs/Web/API/Node/compareDocumentPosition).
+
+```js
+const position = fragmentRef.current.compareDocumentPosition(otherElement);
+```
+
+##### Parameters {/*comparedocumentposition-parameters*/}
+
+* `otherNode`: The DOM node to compare against.
+
+##### Returns {/*comparedocumentposition-returns*/}
+
+A bitmask of [position flags](https://developer.mozilla.org/en-US/docs/Web/API/Node/compareDocumentPosition#return_value). Empty Fragments and Fragments with children rendered through a [portal](/reference/react-dom/createPortal) include `Node.DOCUMENT_POSITION_IMPLEMENTATION_SPECIFIC` in the result.
+
+---
+
+#### `scrollIntoView(alignToTop?)` {/*scrollintoview*/}
+
+Scrolls the Fragment's children into view. When `alignToTop` is `true` or omitted, scrolls to align the first child with the top of the scrollable ancestor. When `alignToTop` is `false`, scrolls to align the last child with the bottom.
+
+```js
+fragmentRef.current.scrollIntoView();
+```
+
+##### Parameters {/*scrollintoview-parameters*/}
+
+* **optional** `alignToTop`: A boolean. If `true` (the default), scrolls the first child to the top of the scrollable area. If `false`, scrolls the last child to the bottom. Unlike [`Element.scrollIntoView()`](https://developer.mozilla.org/en-US/docs/Web/API/Element/scrollIntoView), this method does not accept a `ScrollIntoViewOptions` object.
+
+##### Returns {/*scrollintoview-returns*/}
+
+`scrollIntoView` does not return anything (`undefined`).
+
+##### Caveats {/*scrollintoview-caveats*/}
+
+* `scrollIntoView` does not accept an options object. Passing one throws an error. Use the `alignToTop` boolean instead.
+* When the Fragment has no children, `scrollIntoView` scrolls the nearest sibling or parent into view as a fallback.
+
+---
+
+#### `FragmentInstance` Caveats {/*fragmentinstance-caveats*/}
+
+* Methods that target children (such as `addEventListener`, `observeUsing`, and `getClientRects`) operate on *first-level host (DOM) children* of the Fragment. They do not directly target children nested inside another DOM element.
+* `focus` and `focusLast` search nested children depth-first for focusable elements, unlike event and observer methods which only target first-level host children.
+* `observeUsing` does not work on text nodes. React logs a warning in development if the Fragment contains only text children.
+* React does not apply event listeners added via `addEventListener` to hidden [`<Activity>`](/reference/react/Activity) trees. When an `Activity` boundary switches from hidden to visible, listeners are applied automatically.
+* Each first-level DOM child of a Fragment with a `ref` gets a `reactFragments` property—a `Set<FragmentInstance>` containing all Fragment instances that own the element. This enables [caching a shared observer](#caching-global-intersection-observer) across multiple Fragments.
 
 ---
 
@@ -242,47 +459,312 @@ function PostBody({ body }) {
 
 ---
 
-### <CanaryBadge /> Using Fragment refs for DOM interaction {/*using-fragment-refs-for-dom-interaction*/}
+### <CanaryBadge /> Adding event listeners without a wrapper element {/*adding-event-listeners-without-wrapper*/}
 
-Fragment refs allow you to interact with the DOM nodes wrapped by a Fragment without adding extra wrapper elements. This is useful for event handling, visibility tracking, focus management, and replacing deprecated patterns like `ReactDOM.findDOMNode()`.
+Fragment `ref`s let you add event listeners to a group of elements without adding a wrapper DOM node. Use a [ref callback](/reference/react-dom/components/common#ref-callback) to attach and clean up listeners:
+
+<Sandpack>
 
 ```js
-import { Fragment } from 'react';
+import { Fragment, useState, useRef, useEffect } from 'react';
 
 function ClickableFragment({ children, onClick }) {
+  const fragmentRef = useRef(null);
+  useEffect(() => {
+    const fragmentInstance = fragmentRef.current;
+    if (fragmentInstance === null) {
+      return;
+    }
+    fragmentInstance.addEventListener('click', onClick);
+    return () => {
+      fragmentInstance.removeEventListener(
+        'click',
+        onClick
+      );
+    };
+  }, [onClick])
   return (
-    <Fragment ref={fragmentInstance => {
-      fragmentInstance.addEventListener('click', handleClick);
-      return () => fragmentInstance.removeEventListener('click', handleClick);
-    }}>
+    <Fragment ref={fragmentRef}>
       {children}
     </Fragment>
   );
 }
+
+export default function App() {
+  const [clicks, setClicks] = useState(0);
+
+  return (
+    <>
+      <p>Total clicks: {clicks}</p>
+      <ClickableFragment onClick={() => {
+        setClicks(c => c + 1);
+      }}>
+        <button>Button A</button>
+        <button>Button B</button>
+        <button>Button C</button>
+      </ClickableFragment>
+    </>
+  );
+}
 ```
+
+```json package.json hidden
+{
+  "dependencies": {
+    "react": "canary",
+    "react-dom": "canary",
+    "react-scripts": "latest"
+  }
+}
+```
+
+</Sandpack>
+
+The `addEventListener` call applies the listener to every first-level DOM child of the Fragment. When children are dynamically added or removed, the `FragmentInstance` automatically adds or removes the listener.
+
+<DeepDive>
+
+#### Which children does a Fragment ref target? {/*which-children-does-a-fragment-ref-target*/}
+
+A `FragmentInstance` targets the **first-level host (DOM) children** of the Fragment. Consider this tree:
+
+```js
+<Fragment ref={ref}>
+  <div id="A" />
+  <Wrapper>
+    <div id="B">
+      <div id="C" />
+    </div>
+  </Wrapper>
+  <div id="D" />
+</Fragment>
+```
+
+`Wrapper` is a React component, so the `FragmentInstance` looks through it to find DOM nodes. The targeted children are `A`, `B`, and `D`. `C` is not targeted because it is nested inside the DOM element `B`.
+
+Methods like `addEventListener`, `observeUsing`, and `getClientRects` operate on these first-level DOM children. `focus` and `focusLast` are different—they search *all* nested children depth-first to find focusable elements.
+
+</DeepDive>
+
+---
+
+### <CanaryBadge /> Managing focus across a group of elements {/*managing-focus-across-elements*/}
+
+Fragment `ref`s provide `focus`, `focusLast`, and `blur` methods that operate across all DOM nodes within the Fragment:
+
+<Sandpack>
+
+```js
+import { Fragment, useRef } from 'react';
+
+function FormFields({ children }) {
+  const fragmentRef = useRef(null);
+
+  return (
+    <>
+      <div className="buttons">
+        <button onClick={() => {
+          fragmentRef.current.focus();
+        }}>
+          Focus first
+        </button>
+        <button onClick={() => {
+          fragmentRef.current.focusLast();
+        }}>
+          Focus last
+        </button>
+        <button onClick={() => {
+          fragmentRef.current.blur();
+        }}>
+          Blur
+        </button>
+      </div>
+      <Fragment ref={fragmentRef}>
+        {children}
+      </Fragment>
+    </>
+  );
+}
+
+// Even though the inputs are deeply nested,
+// focus() searches depth-first to find them.
+export default function App() {
+  return (
+    <FormFields>
+      <fieldset>
+        <legend>Shipping</legend>
+        <label>
+          Street: <input name="street" />
+        </label>
+        <label>
+          City: <input name="city" />
+        </label>
+      </fieldset>
+    </FormFields>
+  );
+}
+```
+
+```css
+.buttons {
+  display: flex;
+  gap: 8px;
+  margin-bottom: 10px;
+}
+
+label {
+  display: inline-block;
+}
+```
+
+```json package.json hidden
+{
+  "dependencies": {
+    "react": "canary",
+    "react-dom": "canary",
+    "react-scripts": "latest"
+  }
+}
+```
+
+</Sandpack>
+
+Calling `focus()` focuses the `street` input—even though it is nested inside a `<fieldset>` and `<label>`. `focus()` searches depth-first through all nested children, not just direct children of the Fragment. `focusLast()` does the same in reverse, and `blur()` removes focus if the currently focused element is within the Fragment.
+
 ---
 
-### <CanaryBadge /> Tracking visibility with Fragment refs {/*tracking-visibility-with-fragment-refs*/}
+### <CanaryBadge /> Scrolling a group of elements into view {/*scrolling-group-into-view*/}
 
-Fragment refs are useful for visibility tracking and intersection observation. This enables you to monitor when content becomes visible without requiring the child Components to expose refs:
+Use `scrollIntoView` to scroll a Fragment's children into view without a wrapper element. Pass `true` (or omit the argument) to scroll the first child to the top. Pass `false` to scroll the last child to the bottom:
 
-```js {19,21,31-34}
-import { Fragment, useRef, useLayoutEffect } from 'react';
+<Sandpack>
 
-function VisibilityObserverFragment({ threshold = 0.5, onVisibilityChange, children }) {
+```js
+import { Fragment, useRef } from 'react';
+
+function ScrollableSection({ children }) {
+  const fragmentRef = useRef(null);
+
+  return (
+    <>
+      <div className="buttons">
+        <button onClick={() => {
+          fragmentRef.current.scrollIntoView();
+        }}>
+          Scroll to top
+        </button>
+        <button onClick={() => {
+          fragmentRef.current.scrollIntoView(false);
+        }}>
+          Scroll to bottom
+        </button>
+      </div>
+      <div className="container">
+        <Fragment ref={fragmentRef}>
+          {children}
+        </Fragment>
+      </div>
+    </>
+  );
+}
+
+const items = [];
+for (let i = 1; i <= 25; i++) {
+  items.push('Item ' + i);
+}
+
+export default function App() {
+  return (
+    <ScrollableSection>
+      <h3>Section Start</h3>
+      {items.map((item) => (
+        <p key={item}>{item}</p>
+      ))}
+      <h3>Section End</h3>
+    </ScrollableSection>
+  );
+}
+```
+
+```css
+.buttons {
+  display: flex;
+  gap: 8px;
+  margin-bottom: 10px;
+}
+
+.container {
+  height: 200px;
+  overflow-y: auto;
+  border: 2px solid #c4c4c4;
+  border-radius: 4px;
+  padding: 10px;
+}
+
+h3 {
+  margin: 4px 0;
+  /* Padding to handle offset of global sticky nav when scrolling for example */
+  padding-top: 4em;
+  color: #1a73e8;
+}
+
+p {
+  margin: 4px 0;
+}
+```
+
+```json package.json hidden
+{
+  "dependencies": {
+    "react": "canary",
+    "react-dom": "canary",
+    "react-scripts": "latest"
+  }
+}
+```
+
+</Sandpack>
+
+---
+
+### <CanaryBadge /> Observing visibility without a wrapper element {/*observing-visibility-without-wrapper*/}
+
+Use `observeUsing` to attach an `IntersectionObserver` to all first-level DOM children of a Fragment. This lets you track visibility without requiring child components to expose `ref`s or adding a wrapper element:
+
+<Sandpack>
+
+```js
+import {
+  Fragment,
+  useRef,
+  useLayoutEffect,
+  useState,
+} from 'react';
+import Card from './Card';
+
+function VisibleGroup({ onVisibilityChange, children }) {
   const fragmentRef = useRef(null);
 
   useLayoutEffect(() => {
+    const visibleElements = new Set();
     const observer = new IntersectionObserver(
       (entries) => {
-        onVisibilityChange(entries.some(entry => entry.isIntersecting))
-      },
-      { threshold }
+        entries.forEach(e => {
+          if (e.isIntersecting) {
+            visibleElements.add(e.target);
+          } else {
+            visibleElements.delete(e.target);
+          }
+        });
+        onVisibilityChange(visibleElements.size > 0);
+      }
     );
-
-    fragmentRef.current.observeUsing(observer);
-    return () => fragmentRef.current.unobserveUsing(observer);
-  }, [threshold, onVisibilityChange]);
+    const fragmentInstance = fragmentRef.current;
+    fragmentInstance.observeUsing(observer);
+    return () => {
+      fragmentInstance.unobserveUsing(observer);
+    };
+  }, [onVisibilityChange]);
 
   return (
     <Fragment ref={fragmentRef}>
@@ -291,38 +773,258 @@ function VisibilityObserverFragment({ threshold = 0.5, onVisibilityChange, child
   );
 }
 
-function MyComponent() {
-  const handleVisibilityChange = (isVisible) => {
-    console.log('Component is', isVisible ? 'visible' : 'hidden');
-  };
+export default function App() {
+  const [isVisible, setIsVisible] = useState(true);
 
   return (
-    <VisibilityObserverFragment onVisibilityChange={handleVisibilityChange}>
-      <SomeThirdPartyComponent />
-      <AnotherComponent />
-    </VisibilityObserverFragment>
+    <div className={isVisible ? 'page visible' : 'page'}>
+      <div className="filler">Scroll down</div>
+      <VisibleGroup onVisibilityChange={setIsVisible}>
+        <Card title="First section" />
+        <Card title="Second section" />
+      </VisibleGroup>
+      <div className="filler">Scroll up</div>
+    </div>
   );
 }
 ```
 
-This pattern is an alternative to Effect-based visibility logging, which is an anti-pattern in most cases. Relying on Effects alone does not guarantee that the rendered Component is observable by the user.
+```css
+.page {
+  transition: background 0.3s;
+}
+
+.page.visible {
+  background: #d4edda;
+}
+
+.filler {
+  height: 500px;
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  color: #aaa;
+  font-size: 14px;
+}
+
+.card {
+  padding: 16px;
+  background: white;
+  border: 1px solid #ddd;
+  border-radius: 8px;
+  margin: 8px 16px;
+  box-shadow: 0 1px 3px rgba(0,0,0,0.08);
+  font-weight: 600;
+  font-size: 14px;
+}
+```
+
+```js src/Card.js hidden
+export default function Card({ title }) {
+  return <div className="card">{title}</div>;
+}
+```
+
+```json package.json hidden
+{
+  "dependencies": {
+    "react": "canary",
+    "react-dom": "canary",
+    "react-scripts": "latest"
+  }
+}
+```
+
+</Sandpack>
 
 ---
 
-### <CanaryBadge /> Focus management with Fragment refs {/*focus-management-with-fragment-refs*/}
+### <CanaryBadge /> Caching a global IntersectionObserver {/*caching-global-intersection-observer*/}
 
-Fragment refs provide focus management methods that work across all DOM nodes within the Fragment:
+A common performance optimization for sites with many observers is to share a single IntersectionObserver per config and route its entries to the correct callbacks based on which element intersected. Fragment `ref`s support this same pattern through the `reactFragments` property.
 
-```js
-import { Fragment, useRef } from 'react';
+Each first-level DOM child of a Fragment with a `ref` has a `reactFragments` property: a `Set` of `FragmentInstance` objects that contain that element. When the shared observer fires, you can use this property to look up which `FragmentInstance` owns the intersecting element and run the right callbacks.
+
+<Sandpack>
+
+```js src/App.js active
+import { useState, useCallback } from 'react';
+import ObservedGroup from './ObservedGroup';
+import Card from './Card';
+
+export default function App() {
+  const [bgColor, setBgColor] = useState(null);
+
+  const onGreen = useCallback((entry) => {
+    if (entry.isIntersecting) {
+      setBgColor('#d4edda');
+    }
+  }, []);
+
+  const onBlue = useCallback((entry) => {
+    if (entry.isIntersecting) {
+      setBgColor('#cce5ff');
+    }
+  }, []);
 
-function FocusFragment({ children }) {
   return (
-    <Fragment ref={(fragmentInstance) => fragmentInstance?.focus()}>
+    <div className="page" style={{
+      background: bgColor || 'white',
+    }}>
+      <div className="filler">Scroll down</div>
+      <ObservedGroup onIntersection={onGreen}>
+        <Card title="Green section" className="green" />
+      </ObservedGroup>
+      <div className="filler" />
+      <ObservedGroup onIntersection={onBlue}>
+        <Card title="Blue section" className="blue" />
+      </ObservedGroup>
+      <div className="filler">Scroll up</div>
+    </div>
+  );
+}
+```
+
+```js src/ObservedGroup.js
+import {
+  Fragment,
+  useRef,
+  useLayoutEffect,
+} from 'react';
+
+const callbackMap = new WeakMap();
+const observerCache = new Map();
+
+function getOptionsKey(options) {
+  const root = options?.root ?? null;
+  const rootMargin = options?.rootMargin ?? '0px';
+  const threshold = options?.threshold ?? 0;
+  return `${rootMargin}|${threshold}`;
+}
+
+function getSharedObserver(
+  fragmentInstance,
+  onIntersection,
+  options,
+) {
+  // Register this callback for the
+  // fragment instance.
+  const existing =
+    callbackMap.get(fragmentInstance);
+  callbackMap.set(
+    fragmentInstance,
+    existing
+      ? [...existing, onIntersection]
+      : [onIntersection],
+  );
+
+  const key = getOptionsKey(options);
+  if (observerCache.has(key)) {
+    return observerCache.get(key);
+  }
+
+  const observer = new IntersectionObserver(
+    (entries) => {
+      for (const entry of entries) {
+        // Look up which FragmentInstances own
+        // this element.
+        const fragmentInstances =
+          entry.target.reactFragments;
+        if (fragmentInstances) {
+          for (const inst of fragmentInstances) {
+            const callbacks =
+              callbackMap.get(inst) || [];
+            callbacks.forEach(cb => cb(entry));
+          }
+        }
+      }
+    },
+    options,
+  );
+
+  observerCache.set(key, observer);
+  return observer;
+}
+
+export default function ObservedGroup({
+  onIntersection,
+  options,
+  children,
+}) {
+  const fragmentRef = useRef(null);
+
+  useLayoutEffect(() => {
+    const fragmentInstance = fragmentRef.current;
+    const observer = getSharedObserver(
+      fragmentInstance,
+      onIntersection,
+      options,
+    );
+    fragmentInstance.observeUsing(observer);
+    return () => {
+      fragmentInstance.unobserveUsing(observer);
+      callbackMap.delete(fragmentInstance);
+    };
+  }, [onIntersection, options]);
+
+  return (
+    <Fragment ref={fragmentRef}>
       {children}
     </Fragment>
   );
 }
 ```
 
-The `focus()` method focuses the first focusable element within the Fragment, while `focusLast()` focuses the last focusable element.
+```css
+.page {
+  transition: background 0.3s;
+}
+
+.filler {
+  height: 500px;
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  color: #aaa;
+  font-size: 14px;
+}
+
+.card {
+  padding: 16px;
+  background: white;
+  border: 1px solid #ddd;
+  border-radius: 8px;
+  margin: 0 16px;
+  box-shadow: 0 1px 3px rgba(0,0,0,0.08);
+  font-weight: 600;
+  font-size: 14px;
+}
+
+.card.green {
+  border-left: 3px solid #28a745;
+}
+
+.card.blue {
+  border-left: 3px solid #007bff;
+}
+```
+
+```js src/Card.js hidden
+export default function Card({ title, className }) {
+  return <div className={'card' + (className ? ' ' + className : '')}>{title}</div>;
+}
+```
+
+```json package.json hidden
+{
+  "dependencies": {
+    "react": "canary",
+    "react-dom": "canary",
+    "react-scripts": "latest"
+  }
+}
+```
+
+</Sandpack>
+
+Multiple `ObservedGroup` components with the same options reuse a single `IntersectionObserver`. When either section scrolls into view, the shared observer fires and uses `reactFragments` to route the entry to the correct callback.

From b4610fbd4410371958587f2fdfd6c43d073cb918 Mon Sep 17 00:00:00 2001
From: Maken Cristhian <96421658+MakenRosa@users.noreply.github.com>
Date: Mon, 22 Jun 2026 12:23:01 -0300
Subject: [PATCH 2/9] Clarify useLayoutEffect setup timing (#8488)

---
 src/content/reference/react/useLayoutEffect.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/content/reference/react/useLayoutEffect.md b/src/content/reference/react/useLayoutEffect.md
index 24b360404..79263b8e7 100644
--- a/src/content/reference/react/useLayoutEffect.md
+++ b/src/content/reference/react/useLayoutEffect.md
@@ -47,7 +47,7 @@ function Tooltip() {
 
 #### Parameters {/*parameters*/}
 
-* `setup`: The function with your Effect's logic. Your setup function may also optionally return a *cleanup* function. Before your [component commits](/learn/render-and-commit#step-3-react-commits-changes-to-the-dom), React will run your setup function. After every commit with changed dependencies, React will first run the cleanup function (if you provided it) with the old values, and then run your setup function with the new values. Before your component is removed from the DOM, React will run your cleanup function.
+* `setup`: The function with your Effect's logic. Your setup function may also optionally return a *cleanup* function. After your [component commits](/learn/render-and-commit#step-3-react-commits-changes-to-the-dom) to the DOM and before the browser repaints the screen, React will run your setup function. After every commit with changed dependencies, React will first run the cleanup function (if you provided it) with the old values, and then run your setup function with the new values. Before your component is removed from the DOM, React will run your cleanup function.
 
 * **optional** `dependencies`: The list of all reactive values referenced inside of the `setup` code. Reactive values include props, state, and all the variables and functions declared directly inside your component body. If your linter is [configured for React](/learn/editor-setup#linting), it will verify that every reactive value is correctly specified as a dependency. The list of dependencies must have a constant number of items and be written inline like `[dep1, dep2, dep3]`. React will compare each dependency with its previous value using the [`Object.is`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/is) comparison. If you omit this argument, your Effect will re-run after every commit of the component.
 

From ecf6c2f191844815923add7ea551fb7b9ba76f6d Mon Sep 17 00:00:00 2001
From: Aurora Scharff <66901228+aurorascharff@users.noreply.github.com>
Date: Wed, 24 Jun 2026 19:12:41 +0200
Subject: [PATCH 3/9] Increase dark-mode button contrast (#8494)

Bumps button contrast to match the treatment on reactnative.dev.

Dark mode:
- primary text: dark:text-secondary (#404756) -> dark:text-gray-90 (#23272F)
- secondary border: #404756 -> #4E5769 (matches RN's rgb(78,86,104))

Light mode:
- secondary border: #D9DBE3 -> #BCC1CD (matches RN's rgb(188,193,205))

gray-90 keeps a subtle cyan tint on the teal button, per review feedback
(gray-95 was too flat).
---
 src/components/ButtonLink.tsx | 2 +-
 tailwind.config.js            | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/components/ButtonLink.tsx b/src/components/ButtonLink.tsx
index bd98d5b38..dff09ed3a 100644
--- a/src/components/ButtonLink.tsx
+++ b/src/components/ButtonLink.tsx
@@ -33,7 +33,7 @@ function ButtonLink({
     className,
     'active:scale-[.98] transition-transform inline-flex font-bold items-center outline-none focus:outline-none focus-visible:outline focus-visible:outline-link focus:outline-offset-2 focus-visible:dark:focus:outline-link-dark leading-snug',
     {
-      'bg-link text-white dark:bg-brand-dark dark:text-secondary hover:bg-opacity-80':
+      'bg-link text-white dark:bg-brand-dark dark:text-gray-90 hover:bg-opacity-80':
         type === 'primary',
       'text-primary dark:text-primary-dark shadow-secondary-button-stroke dark:shadow-secondary-button-stroke-dark hover:bg-gray-40/5 active:bg-gray-40/10 hover:dark:bg-gray-60/5 active:dark:bg-gray-60/10':
         type === 'secondary',
diff --git a/tailwind.config.js b/tailwind.config.js
index 9450cfa59..85d0e7050 100644
--- a/tailwind.config.js
+++ b/tailwind.config.js
@@ -46,8 +46,8 @@ module.exports = {
       'inner-border-dark': 'inset 0 0 0 1px rgba(255, 255, 255, 0.08)',
       'outer-border': '0 0 0 1px rgba(0, 0, 0, 0.1)',
       'outer-border-dark': '0 0 0 1px rgba(255, 255, 255, 0.1)',
-      'secondary-button-stroke': 'inset 0 0 0 1px #D9DBE3',
-      'secondary-button-stroke-dark': 'inset 0 0 0 1px #404756',
+      'secondary-button-stroke': 'inset 0 0 0 1px #BCC1CD',
+      'secondary-button-stroke-dark': 'inset 0 0 0 1px #4E5769',
       none: 'none',
     },
     extend: {

From fb3854a4fc28a5ec853fb3bfdf40a60ed44a7c65 Mon Sep 17 00:00:00 2001
From: Ricky <rickhanlonii@gmail.com>
Date: Wed, 24 Jun 2026 16:31:14 -0400
Subject: [PATCH 4/9] Rewrite `use()` docs (#8305)

* Claude use docs attempt

* Human updates

* Address review feedback

* Address additional review feedback

* Split Pitfall and DeepDive, clarify recreation examples

* Reorder DeepDive: prose before correct example

* Add Reading a Promise from context section

* Address review feedback and align DeepDive with RSC docs style

* Drop inaccurate claim about blocking page rendering

* Address feedback

* Address feedback: clarify use() accepts Promise or context

* Apply suggestion from @rickhanlonii

* Update src/content/reference/react/use.md

Co-authored-by: Ricky <rickhanlonii@gmail.com>

* [use] Add Pitfall on refetching Promises from context in RSCs

---------

Co-authored-by: Aurora Scharff <aurora.sofie@gmail.com>
Co-authored-by: Aurora Scharff <66901228+aurorascharff@users.noreply.github.com>
---
 src/content/reference/react/use.md | 1121 +++++++++++++++++++++++++---
 1 file changed, 997 insertions(+), 124 deletions(-)

diff --git a/src/content/reference/react/use.md b/src/content/reference/react/use.md
index c13ad5203..0fc152c7f 100644
--- a/src/content/reference/react/use.md
+++ b/src/content/reference/react/use.md
@@ -4,7 +4,7 @@ title: use
 
 <Intro>
 
-`use` is a React API that lets you read the value of a resource like a [Promise](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise) or [context](/learn/passing-data-deeply-with-context).
+`use` is a React API that lets you read the value of a [Promise](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise) or [context](/learn/passing-data-deeply-with-context).
 
 ```js
 const value = use(resource);
@@ -18,46 +18,73 @@ const value = use(resource);
 
 ## Reference {/*reference*/}
 
-### `use(resource)` {/*use*/}
+### `use(context)` {/*use-context*/}
 
-Call `use` in your component to read the value of a resource like a [Promise](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise) or [context](/learn/passing-data-deeply-with-context).
+Call `use` with a [context](/learn/passing-data-deeply-with-context) to read its value. Unlike [`useContext`](/reference/react/useContext), `use` can be called within loops and conditional statements like `if`.
 
-```jsx
+```js
 import { use } from 'react';
 
-function MessageComponent({ messagePromise }) {
-  const message = use(messagePromise);
+function Button() {
   const theme = use(ThemeContext);
   // ...
 ```
 
-Unlike React Hooks, `use` can be called within loops and conditional statements like `if`. Like React Hooks, the function that calls `use` must be a Component or Hook.
+[See more examples below.](#usage-context)
+
+#### Parameters {/*context-parameters*/}
 
-When called with a Promise, the `use` API integrates with [`Suspense`](/reference/react/Suspense) and [Error Boundaries](/reference/react/Component#catching-rendering-errors-with-an-error-boundary). The component calling `use` *suspends* while the Promise passed to `use` is pending. If the component that calls `use` is wrapped in a Suspense boundary, the fallback will be displayed.  Once the Promise is resolved, the Suspense fallback is replaced by the rendered components using the data returned by the `use` API. If the Promise passed to `use` is rejected, the fallback of the nearest Error Boundary will be displayed.
+* `context`: A [context](/learn/passing-data-deeply-with-context) created with [`createContext`](/reference/react/createContext).
 
-[See more examples below.](#usage)
+#### Returns {/*context-returns*/}
 
-#### Parameters {/*parameters*/}
+The context value for the passed context, determined by the closest context provider above the calling component. If there is no provider, the returned value is the `defaultValue` passed to [`createContext`](/reference/react/createContext).
 
-* `resource`: this is the source of the data you want to read a value from. A resource can be a [Promise](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise) or a [context](/learn/passing-data-deeply-with-context).
+#### Caveats {/*context-caveats*/}
 
-#### Returns {/*returns*/}
+* `use` must be called inside a Component or a Hook.
+* Reading context with `use` is not supported in [Server Components](/reference/rsc/server-components).
+
+---
 
-The `use` API returns the value that was read from the resource like the resolved value of a [Promise](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise) or [context](/learn/passing-data-deeply-with-context).
+### `use(promise)` {/*use-promise*/}
 
-#### Caveats {/*caveats*/}
+Call `use` with a [Promise](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise) to read its resolved value. The component calling `use` *suspends* while the Promise is pending. Despite its name, `use` is not a Hook. Unlike Hooks, it can be called inside loops and conditional statements like `if`.
 
-* The `use` API must be called inside a Component or a Hook.
-* When fetching data in a [Server Component](/reference/rsc/server-components), prefer `async` and `await` over `use`. `async` and `await` pick up rendering from the point where `await` was invoked, whereas `use` re-renders the component after the data is resolved.
-* Prefer creating Promises in [Server Components](/reference/rsc/server-components) and passing them to [Client Components](/reference/rsc/use-client) over creating Promises in Client Components. Promises created in Client Components are recreated on every render. Promises passed from a Server Component to a Client Component are stable across re-renders. [See this example](#streaming-data-from-server-to-client).
+```js
+import { use } from 'react';
+
+function MessageComponent({ messagePromise }) {
+  const message = use(messagePromise);
+  // ...
+```
+
+If the component that calls `use` is wrapped in a [Suspense](/reference/react/Suspense) boundary, the fallback will be displayed while the Promise is pending. Once the Promise is resolved, the Suspense fallback is replaced by the rendered components using the data returned by `use`. If the Promise is rejected, the fallback of the nearest [Error Boundary](/reference/react/Component#catching-rendering-errors-with-an-error-boundary) will be displayed.
+
+[See more examples below.](#usage-promises)
+
+#### Parameters {/*promise-parameters*/}
+
+* `promise`: A [Promise](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise) whose resolved value you want to read. The Promise must be [cached](#caching-promises-for-client-components) so that the same instance is reused across re-renders.
+
+#### Returns {/*promise-returns*/}
+
+The resolved value of the Promise.
+
+#### Caveats {/*promise-caveats*/}
+
+* `use` must be called inside a Component or a Hook.
+* `use` cannot be called inside a try-catch block. Instead, wrap your component in an [Error Boundary](#displaying-an-error-with-an-error-boundary) to catch the error and display a fallback.
+* Promises passed to `use` must be cached so the same Promise instance is reused across re-renders. [See caching Promises below.](#caching-promises-for-client-components)
+* When passing a Promise from a Server Component to a Client Component, its resolved value must be [serializable](/reference/rsc/use-client#serializable-types).
 
 ---
 
-## Usage {/*usage*/}
+## Usage (Context) {/*usage-context*/}
 
 ### Reading context with `use` {/*reading-context-with-use*/}
 
-When a [context](/learn/passing-data-deeply-with-context) is passed to `use`, it works similarly to [`useContext`](/reference/react/useContext). While `useContext` must be called at the top level of your component, `use` can be called inside conditionals like `if` and loops like `for`. `use` is preferred over `useContext` because it is more flexible.
+When a [context](/learn/passing-data-deeply-with-context) is passed to `use`, it works similarly to [`useContext`](/reference/react/useContext). While `useContext` must be called at the top level of your component, `use` can be called inside conditionals like `if` and loops like `for`.
 
 ```js [[2, 4, "theme"], [1, 4, "ThemeContext"]]
 import { use } from 'react';
@@ -194,11 +221,796 @@ function Button({ show, children }) {
 
 </Sandpack>
 
-### Streaming data from the server to the client {/*streaming-data-from-server-to-client*/}
+### Reading a Promise from context {/*reading-a-promise-from-context*/}
+
+To share asynchronous data without prop drilling, set a Promise as a context value, then read it with `use(context)` and resolve it with `use(promise)`:
 
-Data can be streamed from the server to the client by passing a Promise as a prop from a <CodeStep step={1}>Server Component</CodeStep> to a <CodeStep step={2}>Client Component</CodeStep>.
+```js
+import { use } from 'react';
+import { UserContext } from './UserContext';
+
+function Profile() {
+  const userPromise = use(UserContext);
+  const user = use(userPromise);
+  return <h1>{user.name}</h1>;
+}
+```
+
+Reading the value requires two `use` calls because the context value itself isn't awaited. See [Before you use context](/learn/passing-data-deeply-with-context#before-you-use-context) for alternatives to consider before reaching for context.
+
+Wrap the components that read the Promise in a [Suspense](/reference/react/Suspense) boundary so only that subtree suspends while the Promise is pending. See [Usage (Promises)](#usage-promises) below for more on reading Promises with `use`.
+
+<Pitfall>
+
+When this pattern is used with [Server Components](/reference/rsc/server-components), refetching the Promise requires refetching the Server Component that sets the Promise in context. Avoid setting the Promise in context high in the tree, since that would refetch large parts of the app unnecessarily.
+
+</Pitfall>
+
+---
+
+## Usage (Promises) {/*usage-promises*/}
+
+### Reading a Promise with `use` {/*reading-a-promise-with-use*/}
+
+Call `use` with a Promise to read its resolved value. The component will [suspend](/reference/react/Suspense) while the Promise is pending.
+
+```js [[1, 4, "use(albumsPromise)"]]
+import { use } from 'react';
+
+function Albums({ albumsPromise }) {
+  const albums = use(albumsPromise);
+  return (
+    <ul>
+      {albums.map(album => (
+        <li key={album.id}>
+          {album.title} ({album.year})
+        </li>
+      ))}
+    </ul>
+  );
+}
+```
+
+Wrap the component that calls <CodeStep step={1}>`use`</CodeStep> in a [Suspense](/reference/react/Suspense) boundary so React can show a fallback while the Promise is pending. The closest Suspense boundary above the suspending component shows its fallback. Once the Promise resolves, React reads the value with `use` and replaces the fallback with the rendered component.
+
+<Recipes titleText="Reading a Promise with use vs fetching in an Effect" titleId="examples-promise">
+
+#### Fetching data with `use` {/*fetching-data-with-use*/}
+
+In this example, `Albums` calls `use` with a cached Promise. The component suspends while the Promise is pending, and React displays the nearest Suspense fallback. Rejected Promises propagate to the nearest [Error Boundary](/reference/react/Component#catching-rendering-errors-with-an-error-boundary).
+
+<Sandpack>
+
+```js src/App.js active
+import { use, Suspense } from 'react';
+import { ErrorBoundary } from 'react-error-boundary';
+import { fetchData } from './data.js';
+
+export default function App() {
+  return (
+    <ErrorBoundary fallback={<p>Could not fetch albums.</p>}>
+      <Suspense fallback={<Loading />}>
+        <Albums />
+      </Suspense>
+    </ErrorBoundary>
+  );
+}
+
+function Albums() {
+  const albums = use(fetchData('/albums'));
+  return (
+    <ul>
+      {albums.map(album => (
+        <li key={album.id}>
+          {album.title} ({album.year})
+        </li>
+      ))}
+    </ul>
+  );
+}
+
+function Loading() {
+  return <h2>Loading...</h2>;
+}
+```
+
+```js src/data.js hidden
+// Note: the way you would do data fetching depends on
+// the framework that you use together with Suspense.
+// Normally, the caching logic would be inside a framework.
+
+let cache = new Map();
+
+export function fetchData(url) {
+  if (!cache.has(url)) {
+    cache.set(url, getData(url));
+  }
+  return cache.get(url);
+}
+
+async function getData(url) {
+  if (url === '/albums') {
+    return await getAlbums();
+  } else {
+    throw Error('Not implemented');
+  }
+}
+
+async function getAlbums() {
+  // Add a fake delay to make waiting noticeable.
+  await new Promise(resolve => {
+    setTimeout(resolve, 1000);
+  });
+
+  return [{
+    id: 13,
+    title: 'Let It Be',
+    year: 1970
+  }, {
+    id: 12,
+    title: 'Abbey Road',
+    year: 1969
+  }, {
+    id: 11,
+    title: 'Yellow Submarine',
+    year: 1969
+  }, {
+    id: 10,
+    title: 'The Beatles',
+    year: 1968
+  }];
+}
+```
+
+```json package.json hidden
+{
+  "dependencies": {
+    "react": "19.0.0",
+    "react-dom": "19.0.0",
+    "react-scripts": "^5.0.0",
+    "react-error-boundary": "4.0.3"
+  },
+  "main": "/index.js"
+}
+```
+
+</Sandpack>
+
+<Solution />
+
+#### Fetching data with `useEffect` {/*fetching-data-with-useeffect*/}
+
+Before `use`, a common approach was to fetch data in an Effect and update state when the data arrives. Compared to `use`, this approach requires managing loading and error states manually. For more details on why fetching in an Effect is discouraged, see [You Might Not Need an Effect](/learn/you-might-not-need-an-effect#fetching-data).
+
+<Sandpack>
+
+```js src/App.js active
+import { useState, useEffect } from 'react';
+import { fetchAlbums } from './data.js';
+
+export default function App() {
+  const [albums, setAlbums] = useState(null);
+  const [isLoading, setIsLoading] = useState(true);
+  const [error, setError] = useState(null);
+
+  useEffect(() => {
+    fetchAlbums()
+      .then(data => {
+        setAlbums(data);
+        setIsLoading(false);
+      })
+      .catch(err => {
+        setError(err);
+        setIsLoading(false);
+      });
+  }, []);
+
+  if (isLoading) {
+    return <h2>Loading...</h2>;
+  }
+
+  if (error) {
+    return <p>Error: {error.message}</p>;
+  }
+
+  return (
+    <ul>
+      {albums.map(album => (
+        <li key={album.id}>
+          {album.title} ({album.year})
+        </li>
+      ))}
+    </ul>
+  );
+}
+```
+
+```js src/data.js hidden
+export async function fetchAlbums() {
+  // Add a fake delay to make waiting noticeable.
+  await new Promise(resolve => {
+    setTimeout(resolve, 1000);
+  });
+
+  return [{
+    id: 13,
+    title: 'Let It Be',
+    year: 1970
+  }, {
+    id: 12,
+    title: 'Abbey Road',
+    year: 1969
+  }, {
+    id: 11,
+    title: 'Yellow Submarine',
+    year: 1969
+  }, {
+    id: 10,
+    title: 'The Beatles',
+    year: 1968
+  }];
+}
+```
+
+</Sandpack>
+
+<Solution />
+
+</Recipes>
+
+<Pitfall>
+
+##### Promises passed to `use` must be cached {/*promises-must-cached*/}
+
+Promises created during render are recreated on every render, which causes React to show the Suspense fallback repeatedly and prevents content from appearing.
+
+```js
+function Albums() {
+  // 🔴 `fetch` creates a new Promise on every render.
+  const albums = use(fetch('/albums'));
+  // ...
+}
+```
+
+Instead, pass a Promise from a cache, a Suspense-enabled framework, or a Server Component:
+
+```js
+// ✅ fetchData reads the Promise from a cache.
+const albums = use(fetchData('/albums'));
+```
+
+</Pitfall>
+
+<DeepDive>
+
+#### Why are Promises recreated on every render? {/*why-promises-recreated*/}
+
+[React doesn't preserve state for renders that suspended before mounting](/reference/react/Suspense#caveats). After each suspension, React retries rendering from scratch, so any Promise created during render is recreated.
+
+Common ways a Promise can be unintentionally recreated during render:
+
+```js
+function Albums() {
+  // 🔴 `fetch` creates a new Promise on every render.
+  const albums = use(fetch('/albums'));
+
+  // 🔴 Uncached `async` function calls create a new Promise on every render.
+  const albums = use((async () => {
+    const res = await fetch('/albums');
+    return res.json();
+  })());
+
+  // 🔴 Adding `.then` returns a new Promise on every render,
+  // even if `fetchData` is cached.
+  const albums = use(fetchData('/albums').then(res => res.json()));
+  // ...
+}
+```
+
+Ideally, Promises are created before rendering, such as in an event handler, a route loader, or a Server Component, and passed to the component that calls `use`. Fetching lazily in render delays network requests and can create waterfalls.
+
+```js
+// ✅ fetchData reads the Promise from a cache.
+const albums = use(fetchData('/albums'));
+```
+
+</DeepDive>
+
+---
+
+### Caching Promises for Client Components {/*caching-promises-for-client-components*/}
+
+Promises passed to `use` in Client Components must be cached so the same Promise instance is reused across re-renders. If a new Promise is created directly in render, React will display the Suspense fallback on every re-render.
+
+```js
+// ✅ Cache the Promise so the same one is reused across renders
+let cache = new Map();
+
+export function fetchData(url) {
+  if (!cache.has(url)) {
+    cache.set(url, getData(url));
+  }
+  return cache.get(url);
+}
+```
+
+The `fetchData` function returns the same Promise each time it's called with the same URL. When `use` receives the same Promise on a re-render, it reads the already-resolved value synchronously without suspending.
+
+<Note>
+
+The way you cache Promises depends on the framework you use with Suspense. Frameworks typically provide built-in caching mechanisms. If you don't use a framework, you can use a simple module-level cache like the one above, or a [Suspense-enabled data source](/reference/react/Suspense#displaying-a-fallback-while-content-is-loading).
+
+</Note>
+
+In the example below, clicking "Re-render" updates state in `App` and triggers a re-render. Because `fetchData` returns the same cached Promise, `Albums` reads the value synchronously instead of showing the Suspense fallback again.
+
+<Sandpack>
+
+```js src/App.js active
+import { use, Suspense, useState } from 'react';
+import { fetchData } from './data.js';
+
+export default function App() {
+  const [count, setCount] = useState(0);
+  return (
+    <>
+      <button onClick={() => setCount(count + 1)}>
+        Re-render
+      </button>
+      <p>Render count: {count}</p>
+      <Suspense fallback={<p>Loading...</p>}>
+        <Albums />
+      </Suspense>
+    </>
+  );
+}
+
+function Albums() {
+  const albums = use(fetchData('/albums'));
+  return (
+    <ul>
+      {albums.map(album => (
+        <li key={album.id}>
+          {album.title} ({album.year})
+        </li>
+      ))}
+    </ul>
+  );
+}
+```
+
+```js src/data.js hidden
+// Note: the way you would do data fetching depends on
+// the framework that you use together with Suspense.
+// Normally, the caching logic would be inside a framework.
+
+let cache = new Map();
+
+export function fetchData(url) {
+  if (!cache.has(url)) {
+    cache.set(url, getData(url));
+  }
+  return cache.get(url);
+}
+
+async function getData(url) {
+  if (url === '/albums') {
+    return await getAlbums();
+  } else {
+    throw Error('Not implemented');
+  }
+}
+
+async function getAlbums() {
+  // Add a fake delay to make waiting noticeable.
+  await new Promise(resolve => {
+    setTimeout(resolve, 1000);
+  });
+
+  return [{
+    id: 13,
+    title: 'Let It Be',
+    year: 1970
+  }, {
+    id: 12,
+    title: 'Abbey Road',
+    year: 1969
+  }, {
+    id: 11,
+    title: 'Yellow Submarine',
+    year: 1969
+  }];
+}
+```
+
+</Sandpack>
+
+<DeepDive>
+
+#### How to implement a promise cache {/*how-to-implement-a-promise-cache*/}
+
+A basic cache stores the Promise keyed by URL so the same instance is reused across renders. To also avoid unnecessary Suspense fallbacks when data is already available, you can set `status` and `value` (or `reason`) fields on the Promise. React checks these fields when `use` is called: if `status` is `'fulfilled'`, it reads `value` synchronously without suspending. If `status` is `'rejected'`, it throws `reason`. If the field is missing or `'pending'`, it suspends.
+
+```js
+let cache = new Map();
+
+function fetchData(url) {
+  if (!cache.has(url)) {
+    const promise = getData(url);
+    promise.status = 'pending';
+    promise.then(
+      value => {
+        promise.status = 'fulfilled';
+        promise.value = value;
+      },
+      reason => {
+        promise.status = 'rejected';
+        promise.reason = reason;
+      },
+    );
+    cache.set(url, promise);
+  }
+  return cache.get(url);
+}
+```
+
+This is primarily useful for library authors building Suspense-compatible data layers. React will set the `status` field itself on Promises that don't have it, but setting it yourself avoids an extra render when the data is already available.
+
+This cache pattern is the foundation for [re-fetching data](#re-fetching-data-in-client-components) (where changing the cache key triggers a new fetch) and [preloading data on hover](#preloading-data-on-hover) (where calling `fetchData` early means the Promise may already be resolved by the time `use` reads it).
+
+</DeepDive>
+
+<Pitfall>
+
+Don't conditionally call `use` based on whether a Promise is settled. Always call `use` unconditionally and let React handle reading the `status` field. This ensures React DevTools can show that the component may suspend on data.
+
+```js
+// 🔴 Don't conditionally skip `use`
+if (promise.status === 'fulfilled') {
+  return promise.value;
+}
+const value = use(promise);
+```
+
+```js
+// ✅ Always call `use` unconditionally
+const value = use(promise);
+```
 
-```js [[1, 4, "App"], [2, 2, "Message"], [3, 7, "Suspense"], [4, 8, "messagePromise", 30], [4, 5, "messagePromise"]]
+</Pitfall>
+
+---
+
+### Re-fetching data in Client Components {/*re-fetching-data-in-client-components*/}
+
+To refresh data at the same URL (for example, with a "Refresh" button), invalidate the cache entry and start a new fetch inside a [`startTransition`](/reference/react/startTransition). Store the resulting Promise in state to trigger a re-render. While the new Promise is pending, React keeps showing the existing content because the update is inside a Transition.
+
+```js
+function App() {
+  const [albumsPromise, setAlbumsPromise] = useState(fetchData('/albums'));
+  const [isPending, startTransition] = useTransition();
+
+  function handleRefresh() {
+    startTransition(() => {
+      setAlbumsPromise(refetchData('/albums'));
+    });
+  }
+  // ...
+}
+```
+
+`refetchData` clears the old cache entry and starts a new fetch at the same URL. Storing the resulting Promise in state triggers a re-render inside the Transition. On re-render, `Albums` receives the new Promise and `use` suspends on it while React keeps showing the old content.
+
+<Sandpack>
+
+```js src/App.js active
+import { Suspense, useState, useTransition } from 'react';
+import { use } from 'react';
+import { fetchData, refetchData } from './data.js';
+
+export default function App() {
+  const [albumsPromise, setAlbumsPromise] = useState(
+    () => fetchData('/the-beatles/albums')
+  );
+  const [isPending, startTransition] = useTransition();
+
+  function handleRefresh() {
+    startTransition(() => {
+      setAlbumsPromise(refetchData('/the-beatles/albums'));
+    });
+  }
+
+  return (
+    <>
+      <button
+        onClick={handleRefresh}
+        disabled={isPending}
+      >
+        {isPending ? 'Refreshing...' : 'Refresh'}
+      </button>
+      <div style={{ opacity: isPending ? 0.6 : 1 }}>
+        <Suspense fallback={<Loading />}>
+          <Albums albumsPromise={albumsPromise} />
+        </Suspense>
+      </div>
+    </>
+  );
+}
+
+function Albums({ albumsPromise }) {
+  const albums = use(albumsPromise);
+  return (
+    <ul>
+      {albums.map(album => (
+        <li key={album.id}>
+          {album.title} ({album.year})
+        </li>
+      ))}
+    </ul>
+  );
+}
+
+function Loading() {
+  return <h2>Loading...</h2>;
+}
+```
+
+```js src/data.js hidden
+// Note: the way you would do data fetching depends on
+// the framework that you use together with Suspense.
+// Normally, the caching logic would be inside a framework.
+
+let cache = new Map();
+
+export function fetchData(url) {
+  if (!cache.has(url)) {
+    cache.set(url, getData(url));
+  }
+  return cache.get(url);
+}
+
+export function refetchData(url) {
+  cache.delete(url);
+  return fetchData(url);
+}
+
+async function getData(url) {
+  if (url.startsWith('/the-beatles/albums')) {
+    return await getAlbums();
+  } else {
+    throw Error('Not implemented');
+  }
+}
+
+async function getAlbums() {
+  // Add a fake delay to make waiting noticeable.
+  await new Promise(resolve => {
+    setTimeout(resolve, 1000);
+  });
+
+  return [{
+    id: 13,
+    title: 'Let It Be',
+    year: 1970
+  }, {
+    id: 12,
+    title: 'Abbey Road',
+    year: 1969
+  }, {
+    id: 11,
+    title: 'Yellow Submarine',
+    year: 1969
+  }, {
+    id: 10,
+    title: 'The Beatles',
+    year: 1968
+  }, {
+    id: 9,
+    title: 'Magical Mystery Tour',
+    year: 1967
+  }];
+}
+```
+
+```css
+button { margin-bottom: 10px; }
+```
+
+</Sandpack>
+
+<Note>
+
+Frameworks that support Suspense typically provide their own caching and invalidation mechanisms. The custom cache above is useful for understanding the pattern, but in practice prefer your framework's data fetching solution.
+
+</Note>
+
+---
+
+### Preloading data on hover {/*preloading-data-on-hover*/}
+
+You can start loading data before it's needed by calling `fetchData` during a hover event. Since `fetchData` caches the Promise, the data may already be available by the time the user clicks. If the Promise has resolved by the time `use` reads it, React renders the component immediately without showing a Suspense fallback.
+
+```js
+<button
+  onMouseEnter={() => fetchData(`/${id}/albums`)}
+  onClick={() => {
+    startTransition(() => {
+      setArtistId(id);
+    });
+  }}
+>
+```
+
+In this example, hovering over an artist button starts fetching their albums in the background. Without hovering first, clicking shows a loading fallback. Try hovering over a button for a moment before clicking to see the difference.
+
+<Sandpack>
+
+```js src/App.js active
+import { Suspense, useState, useTransition } from 'react';
+import Albums from './Albums.js';
+import { fetchData } from './data.js';
+
+export default function App() {
+  const [artistId, setArtistId] = useState('the-beatles');
+  const [isPending, startTransition] = useTransition();
+
+  return (
+    <>
+      <div>
+        {['the-beatles', 'led-zeppelin', 'pink-floyd'].map(id => (
+          <button
+            key={id}
+            onMouseEnter={() => {
+              fetchData(`/${id}/albums`);
+            }}
+            onClick={() => {
+              startTransition(() => {
+                setArtistId(id);
+              });
+            }}
+          >
+            {id === 'the-beatles' ? 'The Beatles' :
+             id === 'led-zeppelin' ? 'Led Zeppelin' :
+             'Pink Floyd'}
+          </button>
+        ))}
+      </div>
+      <Suspense key={artistId} fallback={<Loading />}>
+        <Albums artistId={artistId} />
+      </Suspense>
+    </>
+  );
+}
+
+function Loading() {
+  return <h2>Loading...</h2>;
+}
+```
+
+```js src/Albums.js
+import { use } from 'react';
+import { fetchData } from './data.js';
+
+export default function Albums({ artistId }) {
+  const albums = use(fetchData(`/${artistId}/albums`));
+  return (
+    <ul>
+      {albums.map(album => (
+        <li key={album.id}>
+          {album.title} ({album.year})
+        </li>
+      ))}
+    </ul>
+  );
+}
+```
+
+```js src/data.js hidden
+// Note: the way you would do data fetching depends on
+// the framework that you use together with Suspense.
+// Normally, the caching logic would be inside a framework.
+
+let cache = new Map();
+
+export function fetchData(url) {
+  if (!cache.has(url)) {
+    const promise = getData(url);
+    // Set status fields so React can read the value
+    // synchronously if the Promise resolves before
+    // `use` is called (e.g. when preloading on hover).
+    promise.status = 'pending';
+    promise.then(
+      value => {
+        promise.status = 'fulfilled';
+        promise.value = value;
+      },
+      reason => {
+        promise.status = 'rejected';
+        promise.reason = reason;
+      },
+    );
+    cache.set(url, promise);
+  }
+  return cache.get(url);
+}
+
+async function getData(url) {
+  if (url.startsWith('/the-beatles/albums')) {
+    return await getAlbums('the-beatles');
+  } else if (url.startsWith('/led-zeppelin/albums')) {
+    return await getAlbums('led-zeppelin');
+  } else if (url.startsWith('/pink-floyd/albums')) {
+    return await getAlbums('pink-floyd');
+  } else {
+    throw Error('Not implemented');
+  }
+}
+
+async function getAlbums(artistId) {
+  // Add a fake delay to make waiting noticeable.
+  await new Promise(resolve => {
+    setTimeout(resolve, 800);
+  });
+
+  if (artistId === 'the-beatles') {
+    return [{
+      id: 13,
+      title: 'Let It Be',
+      year: 1970
+    }, {
+      id: 12,
+      title: 'Abbey Road',
+      year: 1969
+    }, {
+      id: 11,
+      title: 'Yellow Submarine',
+      year: 1969
+    }];
+  } else if (artistId === 'led-zeppelin') {
+    return [{
+      id: 10,
+      title: 'Coda',
+      year: 1982
+    }, {
+      id: 9,
+      title: 'In Through the Out Door',
+      year: 1979
+    }, {
+      id: 8,
+      title: 'Presence',
+      year: 1976
+    }];
+  } else {
+    return [{
+      id: 7,
+      title: 'The Wall',
+      year: 1979
+    }, {
+      id: 6,
+      title: 'Animals',
+      year: 1977
+    }, {
+      id: 5,
+      title: 'Wish You Were Here',
+      year: 1975
+    }];
+  }
+}
+```
+
+```css
+button { margin-right: 10px; }
+```
+
+</Sandpack>
+
+---
+
+### Streaming data from server to client {/*streaming-data-from-server-to-client*/}
+
+Data can be streamed from the server to the client by passing a Promise as a prop from a Server Component to a Client Component.
+
+```js
 import { fetchMessage } from './lib.js';
 import { Message } from './message.js';
 
@@ -212,9 +1024,9 @@ export default function App() {
 }
 ```
 
-The <CodeStep step={2}>Client Component</CodeStep> then takes <CodeStep step={4}>the Promise it received as a prop</CodeStep> and passes it to the <CodeStep step={5}>`use`</CodeStep> API. This allows the <CodeStep step={2}>Client Component</CodeStep> to read the value from <CodeStep step={4}>the Promise</CodeStep> that was initially created by the Server Component.
+The Client Component then takes the Promise it received as a prop and passes it to the `use` API. This allows the Client Component to read the value from the Promise that was initially created by the Server Component.
 
-```js [[2, 6, "Message"], [4, 6, "messagePromise"], [4, 7, "messagePromise"], [5, 7, "use"]]
+```js
 // message.js
 'use client';
 
@@ -225,7 +1037,7 @@ export function Message({ messagePromise }) {
   return <p>Here is the message: {messageContent}</p>;
 }
 ```
-Because <CodeStep step={2}>`Message`</CodeStep> is wrapped in <CodeStep step={3}>[`Suspense`](/reference/react/Suspense)</CodeStep>, the fallback will be displayed until the Promise is resolved. When the Promise is resolved, the value will be read by the <CodeStep step={5}>`use`</CodeStep> API and the <CodeStep step={2}>`Message`</CodeStep> component will replace the Suspense fallback.
+Because `Message` is wrapped in a [Suspense](/reference/react/Suspense) boundary, the fallback will be displayed until the Promise is resolved. When the Promise is resolved, the value will be read by the `use` API and the `Message` component will replace the Suspense fallback.
 
 <Sandpack>
 
@@ -292,109 +1104,161 @@ root.render(
 
 </Sandpack>
 
-<Note>
-
-When passing a Promise from a Server Component to a Client Component, its resolved value must be serializable to pass between server and client. Data types like functions aren't serializable and cannot be the resolved value of such a Promise.
-
-</Note>
-
-
 <DeepDive>
 
 #### Should I resolve a Promise in a Server or Client Component? {/*resolve-promise-in-server-or-client-component*/}
 
-A Promise can be passed from a Server Component to a Client Component and resolved in the Client Component with the `use` API. You can also resolve the Promise in a Server Component with `await` and pass the required data to the Client Component as a prop.
+A Promise can be resolved with `await` in a Server Component, or passed as a prop to a Client Component and resolved there with `use`.
+
+Using `await` in a Server Component suspends the Server Component itself, and the Client Component receives the resolved value as a prop:
 
 ```js
+// Server Component
 export default async function App() {
+  // Will suspend the Server Component.
   const messageContent = await fetchMessage();
-  return <Message messageContent={messageContent} />
+  return <Message messageContent={messageContent} />;
 }
 ```
 
-But using `await` in a [Server Component](/reference/rsc/server-components) will block its rendering until the `await` statement is finished. Passing a Promise from a Server Component to a Client Component prevents the Promise from blocking the rendering of the Server Component.
+A Server Component can also start a Promise without awaiting it and pass the Promise to a Client Component. The Server Component returns immediately, and the Client Component suspends when it calls `use`:
 
-</DeepDive>
+```js
+// Server Component
+export default function App() {
+  // Not awaited: starts here, resolves on the client.
+  const messagePromise = fetchMessage();
+  return <Message messagePromise={messagePromise} />;
+}
+```
 
-### Dealing with rejected Promises {/*dealing-with-rejected-promises*/}
+```js
+// Client Component
+'use client';
+import { use } from 'react';
 
-In some cases a Promise passed to `use` could be rejected. You can handle rejected Promises by either:
+export function Message({ messagePromise }) {
+  // Will suspend until the data is available.
+  const messageContent = use(messagePromise);
+  return <p>{messageContent}</p>;
+}
+```
 
-1. [Displaying an error to users with an Error Boundary.](#displaying-an-error-to-users-with-error-boundary)
-2. [Providing an alternative value with `Promise.catch`](#providing-an-alternative-value-with-promise-catch)
+Prefer `await` in a Server Component when possible, since it keeps the data fetching on the server. If a Server Component above already awaits the data, pass the resolved value down as a prop instead of creating a new Promise to call `use`.
 
-<Pitfall>
-`use` cannot be called in a try-catch block. Instead of a try-catch block [wrap your component in an Error Boundary](#displaying-an-error-to-users-with-error-boundary), or [provide an alternative value to use with the Promise's `.catch` method](#providing-an-alternative-value-with-promise-catch).
-</Pitfall>
+You can also pass promise as a prop to a Client Component without awaiting it, and then read it with `use(promise)` to suspend deeper in the tree. This allows more of the surrounding UI to complete while the Promise is pending. A common case is interactive content like popovers and tooltips, where the data is needed only after a hover or click. Client Components can't `await`, so they rely on `use` to suspend on a Promise.
 
-#### Displaying an error to users with an Error Boundary {/*displaying-an-error-to-users-with-error-boundary*/}
+In either case, wrap the component that reads the Promise in a Suspense boundary so React can show a fallback while the Promise is pending. See [Revealing content together at once](/reference/react/Suspense#revealing-content-together-at-once) for guidance on boundary placement.
 
-If you'd like to display an error to your users when a Promise is rejected, you can use 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 `use` API in an Error Boundary. If the Promise passed to `use` is rejected the fallback for the Error Boundary will be displayed.
+</DeepDive>
 
-<Sandpack>
+---
 
-```js src/message.js active
-"use client";
+### Displaying an error with an Error Boundary {/*displaying-an-error-with-an-error-boundary*/}
 
-import { use, Suspense } from "react";
+If the Promise passed to `use` is rejected, the error propagates to the nearest [Error Boundary](/reference/react/Component#catching-rendering-errors-with-an-error-boundary). Wrap the component that calls `use` in an Error Boundary to display a fallback when the Promise is rejected.
+
+In the example below, `fetchData` rejects on the first attempt and succeeds on retry. The Error Boundary catches the rejection and shows a fallback with a "Try again" button.
+
+<Sandpack>
+
+```js src/App.js active
+import { use, Suspense, useState, startTransition } from "react";
 import { ErrorBoundary } from "react-error-boundary";
+import { fetchData, refetchData } from "./data.js";
+
+export default function App() {
+  const [albumsPromise, setAlbumsPromise] = useState(
+    () => fetchData('/the-beatles/albums')
+  );
+
+  function handleRetry() {
+    startTransition(() => {
+      setAlbumsPromise(refetchData('/the-beatles/albums'));
+    });
+  }
 
-export function MessageContainer({ messagePromise }) {
   return (
-    <ErrorBoundary fallback={<p>⚠️Something went wrong</p>}>
-      <Suspense fallback={<p>⌛Downloading message...</p>}>
-        <Message messagePromise={messagePromise} />
+    <ErrorBoundary
+      resetKeys={[albumsPromise]}
+      fallbackRender={() => (
+        <>
+          <p>⚠️ Something went wrong loading the albums.</p>
+          <button onClick={handleRetry}>Try again</button>
+        </>
+      )}
+    >
+      <Suspense fallback={<p>Loading...</p>}>
+        <Albums albumsPromise={albumsPromise} />
       </Suspense>
     </ErrorBoundary>
   );
 }
 
-function Message({ messagePromise }) {
-  const content = use(messagePromise);
-  return <p>Here is the message: {content}</p>;
+function Albums({ albumsPromise }) {
+  const albums = use(albumsPromise);
+  return (
+    <ul>
+      {albums.map(album => (
+        <li key={album.id}>
+          {album.title} ({album.year})
+        </li>
+      ))}
+    </ul>
+  );
 }
 ```
 
-```js src/App.js hidden
-import { useState } from "react";
-import { MessageContainer } from "./message.js";
-
-function fetchMessage() {
-  return new Promise((resolve, reject) => setTimeout(reject, 1000));
-}
+```js src/data.js hidden
+// Note: the way you would do data fetching depends on
+// the framework that you use together with Suspense.
+// Normally, the caching logic would be inside a framework.
 
-export default function App() {
-  const [messagePromise, setMessagePromise] = useState(null);
-  const [show, setShow] = useState(false);
-  function download() {
-    setMessagePromise(fetchMessage());
-    setShow(true);
-  }
+let cache = new Map();
+let retried = false;
 
-  if (show) {
-    return <MessageContainer messagePromise={messagePromise} />;
-  } else {
-    return <button onClick={download}>Download message</button>;
+export function fetchData(url) {
+  if (!cache.has(url)) {
+    cache.set(url, getData(url));
   }
+  return cache.get(url);
 }
-```
-
-```js src/index.js hidden
-import React, { StrictMode } from 'react';
-import { createRoot } from 'react-dom/client';
-import './styles.css';
 
-// TODO: update this example to use
-// the Codesandbox Server Component
-// demo environment once it is created
-import App from './App';
+export function refetchData(url) {
+  cache.delete(url);
+  retried = true;
+  return fetchData(url);
+}
 
-const root = createRoot(document.getElementById('root'));
-root.render(
-  <StrictMode>
-    <App />
-  </StrictMode>
-);
+async function getData(url) {
+  // Add a fake delay to make the loading state visible.
+  await new Promise(resolve => setTimeout(resolve, 1000));
+  if (url === '/the-beatles/albums') {
+    // Fail the first attempt to demonstrate the Error Boundary,
+    // then succeed on retry.
+    if (!retried) {
+      throw new Error('Example Error: Failed to fetch albums');
+    }
+    return [{
+      id: 13,
+      title: 'Let It Be',
+      year: 1970
+    }, {
+      id: 12,
+      title: 'Abbey Road',
+      year: 1969
+    }, {
+      id: 11,
+      title: 'Yellow Submarine',
+      year: 1969
+    }, {
+      id: 10,
+      title: 'The Beatles',
+      year: 1968
+    }];
+  }
+  throw new Error('Not implemented');
+}
 ```
 
 ```json package.json hidden
@@ -410,53 +1274,62 @@ root.render(
 ```
 </Sandpack>
 
-#### Providing an alternative value with `Promise.catch` {/*providing-an-alternative-value-with-promise-catch*/}
+---
 
-If you'd like to provide an alternative value when the Promise passed to `use` is rejected you can use the Promise's <CodeStep step={1}>[`catch`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise/catch)</CodeStep> method.
+## Troubleshooting {/*troubleshooting*/}
 
-```js [[1, 6, "catch"],[2, 7, "return"]]
-import { Message } from './message.js';
+### I'm getting an error: "Suspense Exception: This is not a real error!" {/*suspense-exception-error*/}
 
-export default function App() {
-  const messagePromise = new Promise((resolve, reject) => {
-    reject();
-  }).catch(() => {
-    return "no new message found.";
-  });
+You are calling `use` inside a try-catch block. `use` throws internally to integrate with Suspense, so it cannot be wrapped in try-catch. Instead, wrap the component that calls `use` in an [Error Boundary](#displaying-an-error-with-an-error-boundary) to handle errors.
 
-  return (
-    <Suspense fallback={<p>waiting for message...</p>}>
-      <Message messagePromise={messagePromise} />
-    </Suspense>
-  );
-}
+```jsx
+function Albums({ albumsPromise }) {
+  try {
+    // ❌ Don't wrap `use` in try-catch
+    const albums = use(albumsPromise);
+  } catch (e) {
+    return <p>Error</p>;
+  }
+  // ...
 ```
 
-To use the Promise's <CodeStep step={1}>`catch`</CodeStep> method, call <CodeStep step={1}>`catch`</CodeStep> on the Promise object. <CodeStep step={1}>`catch`</CodeStep> takes a single argument: a function that takes an error message as an argument. Whatever is <CodeStep step={2}>returned</CodeStep> by the function passed to <CodeStep step={1}>`catch`</CodeStep> will be used as the resolved value of the Promise.
+Instead, wrap the component in an Error Boundary:
 
----
+```jsx
+function Albums({ albumsPromise }) {
+  // ✅ Call `use` without try-catch
+  const albums = use(albumsPromise);
+  // ...
+```
 
-## Troubleshooting {/*troubleshooting*/}
+```jsx
+// ✅ Use an Error Boundary to handle errors
+<ErrorBoundary fallback={<p>Error</p>}>
+  <Albums albumsPromise={albumsPromise} />
+</ErrorBoundary>
+```
 
-### "Suspense Exception: This is not a real error!" {/*suspense-exception-error*/}
+---
 
-You are either calling `use` outside of a React Component or Hook function, or calling `use` in a try–catch block. If you are calling `use` inside a try–catch block, wrap your component in an Error Boundary, or call the Promise's `catch` to catch the error and resolve the Promise with another value. [See these examples](#dealing-with-rejected-promises).
+### I'm getting a warning: "A component was suspended by an uncached promise" {/*uncached-promise-error*/}
 
-If you are calling `use` outside a React Component or Hook function, move the `use` call to a React Component or Hook function.
+The Promise passed to `use` is not cached, so React cannot reuse it across re-renders.
 
-```jsx
-function MessageComponent({messagePromise}) {
-  function download() {
-    // ❌ the function calling `use` is not a Component or Hook
-    const message = use(messagePromise);
-    // ...
+This commonly happens when calling `fetch` or an `async` function directly in render:
+
+```js
+function Albums() {
+  // 🔴 This creates a new Promise on every render
+  const albums = use(fetch('/albums'));
+  // ...
+}
 ```
 
-Instead, call `use` outside any component closures, where the function that calls `use` is a Component or Hook.
+To fix this, cache the Promise so the same instance is reused:
 
-```jsx
-function MessageComponent({messagePromise}) {
-  // ✅ `use` is being called from a component.
-  const message = use(messagePromise);
-  // ...
+```js
+// ✅ fetchData returns the same Promise for the same URL
+const albums = use(fetchData('/albums'));
 ```
+
+See [caching Promises for Client Components](#caching-promises-for-client-components) for more details.

From b6e9b3c44da5f02d016b218da239dd466df7ac14 Mon Sep 17 00:00:00 2001
From: Aurora Scharff <aurora.sofie@gmail.com>
Date: Wed, 24 Jun 2026 22:39:15 +0200
Subject: [PATCH 5/9] [form] Document onSubmit event handler alongside action

---
 .../reference/react-dom/components/form.md    | 39 ++++++++++++++++++-
 1 file changed, 37 insertions(+), 2 deletions(-)

diff --git a/src/content/reference/react-dom/components/form.md b/src/content/reference/react-dom/components/form.md
index 1043b13a0..9c078aa02 100644
--- a/src/content/reference/react-dom/components/form.md
+++ b/src/content/reference/react-dom/components/form.md
@@ -48,9 +48,44 @@ To create interactive controls for submitting information, render the [built-in
 
 ## Usage {/*usage*/}
 
-### Handle form submission on the client {/*handle-form-submission-on-the-client*/}
+### Handle form submission with an event handler {/*handle-form-submission-with-an-event-handler*/}
 
-Pass a function to the `action` prop of form to run the function when the form is submitted. [`formData`](https://developer.mozilla.org/en-US/docs/Web/API/FormData) will be passed to the function as an argument so you can access the data submitted by the form. This differs from the conventional [HTML action](https://developer.mozilla.org/en-US/docs/Web/HTML/Element/form#action), which only accepts URLs. After the `action` function succeeds, all uncontrolled field elements in the form are reset.
+Pass a function to the `onSubmit` event handler to run code when the form is submitted. By default, the browser sends the form data to the current URL and refreshes the page, so call [`e.preventDefault()`](https://developer.mozilla.org/en-US/docs/Web/API/Event/preventDefault) to override that behavior. Read the submitted data with [`new FormData(e.target)`](https://developer.mozilla.org/en-US/docs/Web/API/FormData).
+
+<Sandpack>
+
+```js src/App.js
+export default function Search() {
+  function handleSubmit(e) {
+    // Prevent the browser from reloading the page
+    e.preventDefault();
+
+    // Read the form data
+    const formData = new FormData(e.target);
+    const query = formData.get("query");
+    alert(`You searched for '${query}'`);
+  }
+
+  return (
+    <form onSubmit={handleSubmit}>
+      <input name="query" />
+      <button type="submit">Search</button>
+    </form>
+  );
+}
+```
+
+</Sandpack>
+
+<Note>
+
+Reading form data with `onSubmit` works in every version of React and gives you direct access to the [submit event](https://developer.mozilla.org/en-US/docs/Web/API/HTMLFormElement/submit_event). The `action` prop, described next, builds on this with extra features like automatic form resets, pending states with [`useFormStatus`](/reference/react-dom/hooks/useFormStatus), and [Server Functions](/reference/rsc/server-functions).
+
+</Note>
+
+### Handle form submission with an action {/*handle-form-submission-with-an-action*/}
+
+Pass a function to the `action` prop of form to run the function when the form is submitted. [`formData`](https://developer.mozilla.org/en-US/docs/Web/API/FormData) will be passed to the function as an argument so you can access the data submitted by the form. This differs from the conventional [HTML action](https://developer.mozilla.org/en-US/docs/Web/HTML/Element/form#action), which only accepts URLs. Unlike `onSubmit`, an `action` runs in a [Transition](/reference/react/useTransition) and calling `e.preventDefault()` isn't needed. After the `action` function succeeds, all uncontrolled field elements in the form are reset.
 
 <Sandpack>
 

From 1f48fb46a8d1d3b4c8758f18a7aec55323152242 Mon Sep 17 00:00:00 2001
From: Aurora Scharff <aurora.sofie@gmail.com>
Date: Wed, 24 Jun 2026 22:50:49 +0200
Subject: [PATCH 6/9] [form] Refine onSubmit/action framing and address review

---
 src/content/reference/react-dom/components/form.md | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/src/content/reference/react-dom/components/form.md b/src/content/reference/react-dom/components/form.md
index 9c078aa02..10e9c6794 100644
--- a/src/content/reference/react-dom/components/form.md
+++ b/src/content/reference/react-dom/components/form.md
@@ -50,7 +50,9 @@ To create interactive controls for submitting information, render the [built-in
 
 ### Handle form submission with an event handler {/*handle-form-submission-with-an-event-handler*/}
 
-Pass a function to the `onSubmit` event handler to run code when the form is submitted. By default, the browser sends the form data to the current URL and refreshes the page, so call [`e.preventDefault()`](https://developer.mozilla.org/en-US/docs/Web/API/Event/preventDefault) to override that behavior. Read the submitted data with [`new FormData(e.target)`](https://developer.mozilla.org/en-US/docs/Web/API/FormData).
+Pass a function to the `onSubmit` event handler to run code when the form is submitted. By default, the browser sends the form data to the current URL and refreshes the page, so call [`e.preventDefault()`](https://developer.mozilla.org/en-US/docs/Web/API/Event/preventDefault) to override that behavior.
+
+This example reads the submitted values with [`new FormData(e.target)`](https://developer.mozilla.org/en-US/docs/Web/API/FormData), which collects every field by its `name`. This keeps the inputs [uncontrolled](/reference/react-dom/components/input#reading-the-input-values-when-submitting-a-form). If you instead [control an input with state](/reference/react-dom/components/input#controlling-an-input-with-a-state-variable), read from that state on submit rather than from `FormData`.
 
 <Sandpack>
 
@@ -61,7 +63,8 @@ export default function Search() {
     e.preventDefault();
 
     // Read the form data
-    const formData = new FormData(e.target);
+    const form = e.target;
+    const formData = new FormData(form);
     const query = formData.get("query");
     alert(`You searched for '${query}'`);
   }
@@ -79,11 +82,11 @@ export default function Search() {
 
 <Note>
 
-Reading form data with `onSubmit` works in every version of React and gives you direct access to the [submit event](https://developer.mozilla.org/en-US/docs/Web/API/HTMLFormElement/submit_event). The `action` prop, described next, builds on this with extra features like automatic form resets, pending states with [`useFormStatus`](/reference/react-dom/hooks/useFormStatus), and [Server Functions](/reference/rsc/server-functions).
+Reading form data with `onSubmit` works in every version of React and gives you direct access to the [submit event](https://developer.mozilla.org/en-US/docs/Web/API/HTMLFormElement/submit_event), so you can call `e.preventDefault()` and read the data yourself. Passing the function to the `action` prop instead runs the submission in a [Transition](/reference/react/useTransition). React then tracks the pending state, sends thrown errors to the nearest error boundary, and lets the form work with [`useActionState`](/reference/react/useActionState) and [`useOptimistic`](/reference/react/useOptimistic). An `action` can also be a [Server Function](/reference/rsc/server-functions), which `onSubmit` does not support.
 
 </Note>
 
-### Handle form submission with an action {/*handle-form-submission-with-an-action*/}
+### Handle form submission with an action prop {/*handle-form-submission-with-an-action-prop*/}
 
 Pass a function to the `action` prop of form to run the function when the form is submitted. [`formData`](https://developer.mozilla.org/en-US/docs/Web/API/FormData) will be passed to the function as an argument so you can access the data submitted by the form. This differs from the conventional [HTML action](https://developer.mozilla.org/en-US/docs/Web/HTML/Element/form#action), which only accepts URLs. Unlike `onSubmit`, an `action` runs in a [Transition](/reference/react/useTransition) and calling `e.preventDefault()` isn't needed. After the `action` function succeeds, all uncontrolled field elements in the form are reset.
 

From 93f6c2773c368a22d0b84e2e585628838edb4bd2 Mon Sep 17 00:00:00 2001
From: MaxwellCohen <to.email.max@gmail.com>
Date: Thu, 25 Jun 2026 01:34:12 -0500
Subject: [PATCH 7/9] fix: update use.md pitfall to make conditional calling
 clearer (#8499)

* fix: update use.md pitfall to mention that bypassing use can corrupt React's internal state tracking

* Apply suggestion from @rickhanlonii

* Apply suggestion from @rickhanlonii

* Apply suggestion from @rickhanlonii

* Apply suggestion from @rickhanlonii

* Update use.md with caution on bypassing `use`

Add warning about bypassing `use` and its effects on React Suspense.

* Apply suggestion from @rickhanlonii

* Update guidance on using the `use` hook with Promises

Clarify usage of `use` hook regarding Promise handling.

* Clarify usage of `use` with Promises

---------

Co-authored-by: Ricky <rickhanlonii@gmail.com>
---
 src/content/reference/react/use.md | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/src/content/reference/react/use.md b/src/content/reference/react/use.md
index 0fc152c7f..1780f82e7 100644
--- a/src/content/reference/react/use.md
+++ b/src/content/reference/react/use.md
@@ -662,10 +662,13 @@ This cache pattern is the foundation for [re-fetching data](#re-fetching-data-in
 
 <Pitfall>
 
-Don't conditionally call `use` based on whether a Promise is settled. Always call `use` unconditionally and let React handle reading the `status` field. This ensures React DevTools can show that the component may suspend on data.
+Don't skip calling `use` based on whether a Promise is already settled.
+
+Unlike other hooks, `use` can be called inside conditions and loops — but it must always be called for the Promise itself. Never read `promise.status` or `promise.value` directly to bypass `use`; always pass the Promise to `use` and let React handle it.
+
 
 ```js
-// 🔴 Don't conditionally skip `use`
+// 🔴 Don't bypass `use` by reading promise status directly
 if (promise.status === 'fulfilled') {
   return promise.value;
 }
@@ -673,10 +676,12 @@ const value = use(promise);
 ```
 
 ```js
-// ✅ Always call `use` unconditionally
+// ✅ Pass the promise to `use` and let React track the promise
 const value = use(promise);
 ```
 
+Bypassing `use` this way can break React Suspense optimizations and Suspense features for React DevTools. You can `use(promise)` conditionally, but don't conditionally `use(promise)` based on the promise itself.
+
 </Pitfall>
 
 ---

From 12181aeb86178f07d4bb8fa24448cc855dc21504 Mon Sep 17 00:00:00 2001
From: Srijan Dubey <87586713+Srijan-D@users.noreply.github.com>
Date: Sun, 28 Jun 2026 03:59:47 +0530
Subject: [PATCH 8/9] Fix broken internal link in Component reference (anchor)
 (#8344)

* Fix broken internal link in Component reference (anchor)

* chore: trigger CLA check
---
 src/content/reference/react/Component.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/content/reference/react/Component.md b/src/content/reference/react/Component.md
index 3b882f097..f6c8cc4bf 100644
--- a/src/content/reference/react/Component.md
+++ b/src/content/reference/react/Component.md
@@ -1009,7 +1009,7 @@ Deriving state leads to verbose code and makes your components difficult to thin
 
 #### Caveats {/*static-getderivedstatefromprops-caveats*/}
 
-- This method is fired on *every* render, regardless of the cause. This is different from [`UNSAFE_componentWillReceiveProps`](#unsafe_cmoponentwillreceiveprops), which only fires when the parent causes a re-render and not as a result of a local `setState`.
+- This method is fired on *every* render, regardless of the cause. This is different from [`UNSAFE_componentWillReceiveProps`](#unsafe_componentwillreceiveprops), which only fires when the parent causes a re-render and not as a result of a local `setState`.
 
 - This method doesn't have access to the component instance. If you'd like, you can reuse some code between `static getDerivedStateFromProps` and the other class methods by extracting pure functions of the component props and state outside the class definition.
 

From 152a471aa9ac2f6f0f3e64c04f39da790d40cf61 Mon Sep 17 00:00:00 2001
From: Jihwan <hanityx@gmail.com>
Date: Sun, 28 Jun 2026 07:31:05 +0900
Subject: [PATCH 9/9] Fix incorrect links on versions page (#8461)

---
 src/content/versions.md | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/content/versions.md b/src/content/versions.md
index 62be00cc3..b48dc364c 100644
--- a/src/content/versions.md
+++ b/src/content/versions.md
@@ -286,7 +286,7 @@ For versions older than React 15, see [15.react.dev](https://15.react.dev).
 - [React v0.4.0](https://legacy.reactjs.org/blog/2013/07/17/react-v0-4-0.html)
 - [New in React v0.4: Prop Validation and Default Values](https://legacy.reactjs.org/blog/2013/07/11/react-v0-4-prop-validation-and-default-values.html)
 - [New in React v0.4: Autobind by Default](https://legacy.reactjs.org/blog/2013/07/02/react-v0-4-autobind-by-default.html)
-- [React v0.3.3](https://legacy.reactjs.org/blog/2013/07/02/react-v0-4-autobind-by-default.html)
+- [React v0.3.3](https://legacy.reactjs.org/blog/2013/06/21/react-v0-3-3.html)
 
 **Releases**
 - [v0.10.0 (March 2014)](https://github.com/facebook/react/blob/main/CHANGELOG.md#0100-march-21-2014)
@@ -300,7 +300,7 @@ For versions older than React 15, see [15.react.dev](https://15.react.dev).
 - [v0.3.3 (June 2013)](https://github.com/facebook/react/blob/main/CHANGELOG.md#033-june-20-2013)
 - [v0.3.2 (May 2013)](https://github.com/facebook/react/blob/main/CHANGELOG.md#032-may-31-2013)
 - [v0.3.1 (May 2013)](https://github.com/facebook/react/blob/main/CHANGELOG.md#031-may-30-2013)
-- [v0.3.0 (May 2013)](https://github.com/facebook/react/blob/main/CHANGELOG.md#031-may-30-2013)
+- [v0.3.0 (May 2013)](https://github.com/facebook/react/blob/main/CHANGELOG.md#030-may-29-2013)
 
 ### Initial Commit {/*initial-commit*/}