use

use is a React Hook that lets you read the value of a resource like a Promise or Context.

function use<T>(resource: Usable<T>): T

use is different from other React Hooks because it can be called conditionally and inside loops. However, like other Hooks, it can only be called in components or other Hooks.

Parameters

Promise<T> | Context<T>

required

The resource you want to read a value from. A resource can be a Promise or a Context.

Promise: React will suspend until the Promise resolves, then return the resolved value
Context: Works like useContext, returning the current context value

Returns

Returns the resolved value of the resource (the resolved value of the Promise or the context value).

Usage

Reading context with use

When a Context is passed to use, it works similarly to useContext:

import { use } from 'react';
import { ThemeContext } from './ThemeContext';

function Button() {
  const theme = use(ThemeContext);
  return <button className={theme}>Click me</button>;
}

Unlike useContext, use can be called conditionally and in loops:

function HorizontalRule({ show }) {
  // ✅ Conditional use is allowed
  if (show) {
    const theme = use(ThemeContext);
    return <hr className={theme} />;
  }
  return null;
}

Streaming data from the server to the client

Data can be streamed from the server to the client by passing a Promise as a prop:

// Server Component
import { fetchMessage } from './api';

export default async function App() {
  const messagePromise = fetchMessage();
  return <Message messagePromise={messagePromise} />;
}

// Client Component
'use client';
import { use } from 'react';

function Message({ messagePromise }) {
  const message = use(messagePromise);
  return <p>{message}</p>;
}

When passing a Promise from a Server Component to a Client Component, its resolved value must be serializable to pass between server and client.

Dealing with rejected Promises

Wrap your component with an error boundary to handle rejected Promises:

import { use, Suspense } from 'react';
import { ErrorBoundary } from 'react-error-boundary';

function MessageContainer({ messagePromise }) {
  return (
    <ErrorBoundary fallback={<p>Error loading message</p>}>
      <Suspense fallback={<p>Loading message...</p>}>
        <Message messagePromise={messagePromise} />
      </Suspense>
    </ErrorBoundary>
  );
}

function Message({ messagePromise }) {
  const message = use(messagePromise);
  return <p>{message}</p>;
}

Common Patterns

Fetching data with use

Basic
With Error Handling

import { use, Suspense } from 'react';

function UserProfile({ userPromise }) {
  const user = use(userPromise);
  
  return (
    <div>
      <h1>{user.name}</h1>
      <p>{user.email}</p>
    </div>
  );
}

function App() {
  const userPromise = fetchUser(userId);
  
  return (
    <Suspense fallback={<div>Loading...</div>}>
      <UserProfile userPromise={userPromise} />
    </Suspense>
  );
}

import { use, Suspense } from 'react';
import { ErrorBoundary } from 'react-error-boundary';

function UserProfile({ userPromise }) {
  const user = use(userPromise);
  
  return (
    <div>
      <h1>{user.name}</h1>
      <p>{user.email}</p>
    </div>
  );
}

function App() {
  const userPromise = fetchUser(userId);
  
  return (
    <ErrorBoundary fallback={<div>Error loading user</div>}>
      <Suspense fallback={<div>Loading...</div>}>
        <UserProfile userPromise={userPromise} />
      </Suspense>
    </ErrorBoundary>
  );
}

Conditional data fetching

import { use } from 'react';

function UserData({ userId, showDetails }) {
  // ✅ Can call use conditionally
  if (showDetails) {
    const user = use(fetchUser(userId));
    return (
      <div>
        <h2>{user.name}</h2>
        <p>{user.bio}</p>
      </div>
    );
  }
  
  return <div>Basic info only</div>;
}

Reading multiple resources

import { use, Suspense } from 'react';

function Dashboard({ userPromise, postsPromise, statsPromise }) {
  const user = use(userPromise);
  const posts = use(postsPromise);
  const stats = use(statsPromise);
  
  return (
    <div>
      <h1>Welcome, {user.name}!</h1>
      <p>You have {posts.length} posts</p>
      <p>Total views: {stats.views}</p>
    </div>
  );
}

function App() {
  const userPromise = fetchUser();
  const postsPromise = fetchPosts();
  const statsPromise = fetchStats();
  
  return (
    <Suspense fallback={<div>Loading dashboard...</div>}>
      <Dashboard
        userPromise={userPromise}
        postsPromise={postsPromise}
        statsPromise={statsPromise}
      />
    </Suspense>
  );
}

Using with Context

import { use, createContext } from 'react';

const UserContext = createContext(null);

function Profile() {
  const user = use(UserContext);
  
  if (!user) {
    return <p>Please log in</p>;
  }
  
  return <h1>Welcome, {user.name}!</h1>;
}

function App() {
  const [user, setUser] = useState(null);
  
  return (
    <UserContext.Provider value={user}>
      <Profile />
    </UserContext.Provider>
  );
}

Parallel data fetching

import { use, Suspense } from 'react';

function Article({ articleId }) {
  // Start fetching in parallel
  const contentPromise = fetchArticleContent(articleId);
  const commentsPromise = fetchArticleComments(articleId);
  const authorPromise = fetchArticleAuthor(articleId);
  
  return (
    <article>
      <Suspense fallback={<div>Loading content...</div>}>
        <Content contentPromise={contentPromise} />
      </Suspense>
      
      <Suspense fallback={<div>Loading author...</div>}>
        <Author authorPromise={authorPromise} />
      </Suspense>
      
      <Suspense fallback={<div>Loading comments...</div>}>
        <Comments commentsPromise={commentsPromise} />
      </Suspense>
    </article>
  );
}

function Content({ contentPromise }) {
  const content = use(contentPromise);
  return <div>{content}</div>;
}

function Author({ authorPromise }) {
  const author = use(authorPromise);
  return <p>By {author.name}</p>;
}

function Comments({ commentsPromise }) {
  const comments = use(commentsPromise);
  return (
    <ul>
      {comments.map(comment => (
        <li key={comment.id}>{comment.text}</li>
      ))}
    </ul>
  );
}

TypeScript

import { use, createContext } from 'react';

// With Promise
interface User {
  id: string;
  name: string;
  email: string;
}

function UserProfile({ userPromise }: { userPromise: Promise<User> }) {
  const user = use(userPromise);
  return <h1>{user.name}</h1>;
}

// With Context
const ThemeContext = createContext<'light' | 'dark'>('light');

function ThemedButton() {
  const theme = use(ThemeContext);
  return <button className={theme}>Click me</button>;
}

// Generic resource
type Resource<T> = Promise<T> | React.Context<T>;

function DataDisplay<T>({ resource }: { resource: Resource<T> }) {
  const data = use(resource);
  return <div>{JSON.stringify(data)}</div>;
}

Troubleshooting

”use” is not a function or is undefined

Make sure you’re using a version of React that supports use (React 19+):

import { use } from 'react'; // React 19+

The component suspends but never resolves

Make sure your Promise eventually resolves:

// ❌ Promise never resolves
const neverResolves = new Promise(() => {});

// ✅ Promise resolves
const resolves = new Promise(resolve => {
  setTimeout(() => resolve('data'), 1000);
});

Can I use “use” with useMemo?

No, use reads resources synchronously. For Promises, wrap the component in Suspense:

// ❌ Don't memoize promises with use
const data = useMemo(() => use(promise), [promise]);

// ✅ Just use directly (component suspends)
const data = use(promise);

Should I always use “use” for context?

No, useContext is still the primary way to read context. Use use when you need conditional context reading:

// ✅ Regular context reading
function Component() {
  const theme = useContext(ThemeContext);
  return <div className={theme}>Content</div>;
}

// ✅ Conditional context reading
function Component({ showThemed }) {
  if (showThemed) {
    const theme = use(ThemeContext);
    return <div className={theme}>Content</div>;
  }
  return <div>Content</div>;
}

Best Practices

Wrap in Suspense

Always wrap components that use Promises with Suspense:

import { use, Suspense } from 'react';

function App() {
  return (
    <Suspense fallback={<Loading />}>
      <DataComponent dataPromise={fetchData()} />
    </Suspense>
  );
}

Add error boundaries

import { ErrorBoundary } from 'react-error-boundary';

function App() {
  return (
    <ErrorBoundary fallback={<Error />}>
      <Suspense fallback={<Loading />}>
        <DataComponent dataPromise={fetchData()} />
      </Suspense>
    </ErrorBoundary>
  );
}

Start fetching early

// ✅ Good: Start fetching before rendering
function App() {
  const dataPromise = fetchData(); // Start immediately
  return (
    <Suspense fallback={<Loading />}>
      <DataComponent dataPromise={dataPromise} />
    </Suspense>
  );
}

// ❌ Bad: Start fetching during render
function DataComponent() {
  const dataPromise = fetchData(); // Starts later
  const data = use(dataPromise);
  return <div>{data}</div>;
}

Don’t create promises during render

// ❌ Bad: Creates new promise each render
function Component() {
  const data = use(fetch('/api/data').then(r => r.json()));
  return <div>{data}</div>;
}

// ✅ Good: Promise created outside component
const dataPromise = fetch('/api/data').then(r => r.json());

function Component() {
  const data = use(dataPromise);
  return <div>{data}</div>;
}

// ✅ Good: Promise passed as prop
function Component({ dataPromise }) {
  const data = use(dataPromise);
  return <div>{data}</div>;
}

When to use “use”

Use use when:

✅ Reading a Promise in a component
✅ You need conditional Hook calls
✅ Streaming data from server to client
✅ Reading context conditionally

Use useContext when:

✅ Reading context unconditionally
✅ You prefer explicit Hook naming

Use useEffect + useState when:

✅ You need to fetch data client-side without Suspense
✅ You need fine-grained loading states
✅ You’re not using React Server Components

Comparison with other data fetching methods

Method	Suspense	Error Boundary	Conditional	Server/Client
`use(promise)`	Yes	Yes	Yes	Both
`useEffect` + `fetch`	No	No	Yes	Client
Async Server Component	Automatic	Yes	No	Server
React Query / SWR	Optional	Yes	Yes	Client

React Core

Hooks

ReactDOM

Server APIs

Parameters

Returns

Usage

Reading context with use

Streaming data from the server to the client

Dealing with rejected Promises

Common Patterns

Fetching data with use

Conditional data fetching

Reading multiple resources

Using with Context

Parallel data fetching

TypeScript

Troubleshooting

”use” is not a function or is undefined

The component suspends but never resolves

Can I use “use” with useMemo?

Should I always use “use” for context?

Best Practices

Wrap in Suspense

Add error boundaries

Start fetching early

Don’t create promises during render

When to use “use”

Comparison with other data fetching methods

​Parameters

​Returns

​Usage

​Reading context with use

​Streaming data from the server to the client

​Dealing with rejected Promises

​Common Patterns

​Fetching data with use

​Conditional data fetching

​Reading multiple resources

​Using with Context

​Parallel data fetching

​TypeScript

​Troubleshooting

​”use” is not a function or is undefined

​The component suspends but never resolves

​Can I use “use” with useMemo?

​Should I always use “use” for context?

​Best Practices

​Wrap in Suspense

​Add error boundaries

​Start fetching early

​Don’t create promises during render

​When to use “use”

​Comparison with other data fetching methods

Parameters

Returns

Usage

Reading context with use

Streaming data from the server to the client

Dealing with rejected Promises

Common Patterns

Fetching data with use

Conditional data fetching

Reading multiple resources

Using with Context

Parallel data fetching

TypeScript

Troubleshooting

”use” is not a function or is undefined

The component suspends but never resolves

Can I use “use” with useMemo?

Should I always use “use” for context?

Best Practices

Wrap in Suspense

Add error boundaries

Start fetching early

Don’t create promises during render

When to use “use”

Comparison with other data fetching methods