let ReactDOM = require('react-dom'); describe('ReactDOMRoot', () => { let container; beforeEach(() => { jest.resetModules(); container = document.createElement('div'); ReactDOM = require('react-dom'); }); afterEach(() => { jest.restoreAllMocks(); }); // @gate !disableLegacyMode it('deprecation warning for ReactDOM.render', () => { spyOnDev(console, 'error'); ReactDOM.render('Hi', container); expect(container.textContent).toEqual('Hi'); if (__DEV__) { expect(console.error).toHaveBeenCalledTimes(1); expect(console.error.mock.calls[0][0]).toContain( 'ReactDOM.render has not been supported since React 18', ); } }); });