Warning: ReactDOM.render is no longer supported in React 18 when using ReactTestUtils.renderIntoDocument

[raaaahman]

React version: 18.2.0
ReactDOM version: 18.2.0

Steps To Reproduce

1. Setup Jest
2. Create a test file which calls to the ReactTestUtils.renderIntoDocumentmethod
3. Run jest

Example code:

test('component should render', () => {
  const container = renderIntoDocument(<MyComponent/>)

  expect(findRenderedComponentWithType(container, MyComponent)).not.toBeNull()
})

The current behavior

When using ReactTestUtils.renderIntoDocumentin React 18, I have the following warning in the console, that make the test fail:

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

It seems to come from this line in the source code:

react/packages/react-dom/src/test-utils/ReactTestUtils.js

Line 128 in 7b25b96

const div = document.createElement('div');

The expected behavior

I expect the ReactTestUtils.renderIntoDocument method not to trigger a console.error and to return a DOM Node.

I know most of the people are probably using @testing-library/react these days, should we expect the React Test Utilities to be deprecated soon?

Thank you for reading.

[gaearon]

Yeah, TestUtils are essentially on life support. We try not to break them but they're frozen in functionality. renderIntoDocument doesn't do anything useful — it's an alias for ReactDOM.render into a new div (despite the naming). So I suggest to use createRoot directly or use Testing Library.

[raaaahman]

Thank you for the quick reply.

[YLeventhal]

So I suggest to use createRoot directly

@gaearon but the legacy ReactDOM.render returns a reference to the root ReactComponent instance while the new api returns void from render ?

or use Testing Library

I wonder if this is what you meant .... i use the testing library to render the component and place a ref on it so i still have access to the component instance ?

[eryue0220]

Is there any progress on this issue?

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