1# React 19
2 
3React 19 is included in Expo SDK 54. This release simplifies several common patterns.
4 
5## Context Changes
6 
7### useContext → use
8 
9The `use` hook replaces `useContext`:
10 
11```tsx
12// Before (React 18)
13import { useContext } from "react";
14const value = useContext(MyContext);
15 
16// After (React 19)
17import { use } from "react";
18const value = use(MyContext);
19```
20 
21- The `use` hook can also read promises, enabling Suspense-based data fetching.
22- `use` can be called conditionally, this simplifies components that consume multiple contexts.
23 
24### Context.Provider → Context
25 
26Context providers no longer need the `.Provider` suffix:
27 
28```tsx
29// Before (React 18)
30<ThemeContext.Provider value={theme}>
31  {children}
32</ThemeContext.Provider>
33 
34// After (React 19)
35<ThemeContext value={theme}>
36  {children}
37</ThemeContext>
38```
39 
40## ref as a Prop
41 
42### Removing forwardRef
43 
44Components can now receive `ref` as a regular prop. `forwardRef` is no longer needed:
45 
46```tsx
47// Before (React 18)
48import { forwardRef } from "react";
49 
50const Input = forwardRef<TextInput, Props>((props, ref) => {
51  return <TextInput ref={ref} {...props} />;
52});
53 
54// After (React 19)
55function Input({ ref, ...props }: Props & { ref?: React.Ref<TextInput> }) {
56  return <TextInput ref={ref} {...props} />;
57}
58```
59 
60### Migration Steps
61 
621. Remove `forwardRef` wrapper
632. Add `ref` to the props destructuring
643. Update the type to include `ref?: React.Ref<T>`
65 
66## Other React 19 Features
67 
68- **Actions** — Functions that handle async transitions
69- **useOptimistic** — Optimistic UI updates
70- **useFormStatus** — Form submission state (web)
71- **Document Metadata** — Native `<title>` and `<meta>` support (web)
72 
73## Cleanup Checklist
74 
75When upgrading to SDK 54:
76 
77- [ ] Replace `useContext` with `use`
78- [ ] Remove `.Provider` from Context components
79- [ ] Remove `forwardRef` wrappers, use `ref` prop instead
80