<Fragment> (<>...</>)Link for this heading

January 6, 2025 · View on GitHub

<Fragment>, often used via <>...</> syntax, lets you group elements without a wrapper node.

<>

  <OneChild />

  <AnotherChild />

</>

Reference
- <Fragment>
Usage

Reference Link for Reference

`<Fragment>`Link for this heading

Wrap elements in <Fragment> to group them together in situations where you need a single element. Grouping elements in Fragment has no effect on the resulting DOM; it is the same as if the elements were not grouped. The empty JSX tag <></> is shorthand for <Fragment></Fragment> in most cases.

Props Link for Props

optional key: Fragments declared with the explicit <Fragment> syntax may have keys.

Caveats Link for Caveats

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>.
React does not reset 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.

Usage Link for Usage

Returning multiple elements Link for Returning multiple elements

Use Fragment, or the equivalent <>...</> syntax, to group multiple elements together. You can use it to put multiple elements in any place where a single element can go. For example, a component can only return one element, but by using a Fragment you can group multiple elements together and then return them as a group:

function Post() {

  return (

    <>

      <PostTitle />

      <PostBody />

    </>

  );

}

Fragments are useful because grouping elements with a Fragment has no effect on layout or styles, unlike if you wrapped the elements in another container like a DOM element. If you inspect this example with the browser tools, you’ll see that all <h1> and <article> DOM nodes appear as siblings without wrappers around them:

App.js

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export default function Blog() {
  return (
    <>
      <Post title="An update" body="It's been a while since I posted..." />
      <Post title="My new blog" body="I am starting a new blog!" />
    </>
  )
}

function Post({ title, body }) {
  return (
    <>
      <PostTitle title={title} />
      <PostBody body={body} />
    </>
  );
}

function PostTitle({ title }) {
  return <h1>{title}</h1>
}

function PostBody({ body }) {
  return (
    <article>
      <p>{body}</p>
    </article>
  );
}

Deep Dive

How to write a Fragment without the special syntax?Link for How to write a Fragment without the special syntax?

Show Details

The example above is equivalent to importing Fragment from React:

import { Fragment } from 'react';

function Post() {

  return (

    <Fragment>

      <PostTitle />

      <PostBody />

    </Fragment>

  );

}

Usually you won’t need this unless you need to pass a key to your Fragment.

Assigning multiple elements to a variable Link for Assigning multiple elements to a variable

Like any other element, you can assign Fragment elements to variables, pass them as props, and so on:

function CloseDialog() {

  const buttons = (

    <>

      <OKButton />

      <CancelButton />

    </>

  );

  return (

    <AlertDialog buttons={buttons}>

      Are you sure you want to leave this page?

    </AlertDialog>

  );

}

Grouping elements with text Link for Grouping elements with text

You can use Fragment to group text together with components:

function DateRangePicker({ start, end }) {

  return (

    <>

      From

      <DatePicker date={start} />

      to

      <DatePicker date={end} />

    </>

  );

}

Rendering a list of Fragments Link for Rendering a list of Fragments

Here’s a situation where you need to write Fragment explicitly instead of using the <></> syntax. When you render multiple elements in a loop, you need to assign a key to each element. If the elements within the loop are Fragments, you need to use the normal JSX element syntax in order to provide the key attribute:

function Blog() {

  return posts.map(post =>

    <Fragment key={post.id}>

      <PostTitle title={post.title} />

      <PostBody body={post.body} />

    </Fragment>

  );

}

You can inspect the DOM to verify that there are no wrapper elements around the Fragment children:

App.js

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import { Fragment } from 'react';

const posts = [
  { id: 1, title: 'An update', body: "It's been a while since I posted..." },
  { id: 2, title: 'My new blog', body: 'I am starting a new blog!' }
];

export default function Blog() {
  return posts.map(post =>
    <Fragment key={post.id}>
      <PostTitle title={post.title} />
      <PostBody body={post.body} />
    </Fragment>
  );
}

function PostTitle({ title }) {
  return <h1>{title}</h1>
}

function PostBody({ body }) {
  return (
    <article>
      <p>{body}</p>
    </article>
  );
}