react.dev/content/docs/addons.md

id	title	permalink
addons	Add-Ons	docs/addons.html

Note:

React.addons entry point is deprecated as of React v15.5. The add-ons have moved to separate modules, and some of them have been deprecated.

The React add-ons are a collection of useful utility modules for building React apps. These should be considered experimental and tend to change more often than the core.

• createFragment, to create a set of externally-keyed children.

The add-ons below are in the development (unminified) version of React only:

• Perf, a performance profiling tool for finding optimization opportunities.
• ReactTestUtils, simple helpers for writing test cases.

Legacy Add-ons

The add-ons below are considered legacy and their use is discouraged. They will keep working in observable future, but there is no further development.

• PureRenderMixin. Use React.PureComponent instead.
• shallowCompare, a helper function that performs a shallow comparison for props and state in a component to decide if a component should update. We recommend using React.PureComponent instead.
• update. Use kolodny/immutability-helper instead.
• ReactDOMFactories, pre-configured DOM factories to make React easier to use without JSX.

Deprecated Add-ons

• LinkedStateMixin has been deprecated.
• TransitionGroup and CSSTransitionGroup have been deprecated in favor of their drop-in replacements.

Using React with Add-ons

You can install the add-ons individually from npm (e.g. npm install react-addons-create-fragment) and import them:

import createFragment from 'react-addons-create-fragment'; // ES6
var createFragment = require('react-addons-create-fragment'); // ES5 with npm

When using React 15 or earlier from a CDN, you can use react-with-addons.js instead of react.js:

<script src="https://unpkg.com/react@15/dist/react-with-addons.js"></script>

The add-ons will be available via the React.addons global (e.g. React.addons.TestUtils).