React Testing Library gives console error for ReactDOM.render in React 18

Question

After updating to React 18 or creating a new React 18 app from create-react-app, when I run the yarn test command, it gives a console.error as a Warning for each of the render methods used in any of the tests as:

console.error
Warning: ReactDOM.render is no longer supported in React 18. Use createRoot instead. Until you switch to the new API, your app will behave as if it's running React 17. Learn more: https://reactjs.org/link/switch-to-createroot

As seen in the screenshot:

As React Testing Library doesn't seem to support React 18 methodology as of now.

Kid

duplicate: #71668756 – Inexpensive

Answer 1

To solve the react testing library error:

"ReactDOM.render is no longer supported in React 18, update the version of the react testing library."

Open your terminal in the root directory of your project and run the following commands:

npm install --save-dev @testing-library/react@latest
npm install --save-dev @testing-library/jest-dom@latest
npm install --save-dev @testing-library/user-event@latest

Make sure to update the versions of all react testing library packages you are using.

Your index.js file should use the new createRoot API to render your application.

index.js

import React from 'react';
import ReactDOM from "react-dom/client";

import App from './App';

const root = ReactDOM.createRoot(document.getElementById("root"));

root.render(
  <React.StrictMode>
    <App />
  </React.StrictMode>
);

Now you should be able to start your tests without getting the error.

App.test.js

import {render, screen} from '@testing-library/react';
import App from './App';

test('renders react component', () => {
  render(<App />);
  const divElement = screen.getByText(/hello world/i);
  expect(divElement).toBeInTheDocument();
});

Peep

to be honest, at first, I didn't believe your answer. because I just create new app using create-react-app so I guessed that the react and react-testing library should be latest version. but in fact react version was 18 but testing library version was old, so I tried your answer and the issue disappeared. – Prospectus

This is nice for the App file itself, but what about other testing components in the project? Should we render them every time we are creating their tests? – Femi

Thank you! Along with above listed packages, I need to upgrade @types/jest to latest due to dependency conflicts. npm install --save-dev @types/jest@latest – Britannia

Answer 2

uninstall @testing-library/react-hook and import renderHook from @testing-library/react

import { renderHook } from "@testing-library/react";

see here https://github.com/testing-library/react-hooks-testing-library/issues/826#issuecomment-1100650242

Emplane

@testing-library/react does not support waitForNextUpdate and async operations the same way @testing-library/react-hook does – Wove

Answer 3

For quick update of all the libraries you can use next commands:

1. for update to new major version: npm install -g npm-check-updates
2. upgrade versions in package.json: ncu -u
3. or npm install, in case your project hasn't node_modules: npm update

Holmen

I would be careful with ncu. It's a great tool but it will also update dependencies that are version locked (i.e. to a specific version or to a specific major version). Ultimately, just have to be paying attention. – Lita