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

user_7610978 0
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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: react testing library warning

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

react-dom react-testing-library jestjs reactjs unit-testing
3 Answers

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();
});
user_182866240

After some findings, and reading the docs from React Testing Library, I could solve the issue for the time being by suppressing the warning precisely related to ReactDOM.render is no longer supported in React 18.

To suppress this warning, you can update the setupTests.ts file present in your src directory and write the snippet of this warning suppression as follows:

import '@testing-library/jest-dom';
    
//***Add This***
const originalError = console.error;
beforeAll(() => {
  console.error = (...args) => {
    if (/Warning: ReactDOM.render is no longer supported in React 18./.test(args[0])) {
      return;
    }
    originalError.call(console, ...args);
  };
});

afterAll(() => {
  console.error = originalError;
});

This should solve the issue and suppress the warnings.

user_76109780

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
user_139592110
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