ReactMultiChild-test.js — react Source File

Source Code

/**
 * Copyright (c) Meta Platforms, Inc. and affiliates.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 *
 * @emails react-core
 */

'use strict';

describe('ReactMultiChild', () => {
  let React;
  let ReactDOMClient;
  let act;
  let assertConsoleErrorDev;

  beforeEach(() => {
    jest.resetModules();
    React = require('react');
    ReactDOMClient = require('react-dom/client');
    act = require('internal-test-utils').act;
    assertConsoleErrorDev =
      require('internal-test-utils').assertConsoleErrorDev;
  });

  describe('reconciliation', () => {
    it('should update children when possible', async () => {
      const container = document.createElement('div');
      const root = ReactDOMClient.createRoot(container);

      const mockMount = jest.fn();
      const mockUpdate = jest.fn();
      const mockUnmount = jest.fn();

      class MockComponent extends React.Component {
        componentDidMount = mockMount;
        componentDidUpdate = mockUpdate;
        componentWillUnmount = mockUnmount;
        render() {
          return <span />;
        }
      }

      expect(mockMount).toHaveBeenCalledTimes(0);
      expect(mockUpdate).toHaveBeenCalledTimes(0);
      expect(mockUnmount).toHaveBeenCalledTimes(0);

      await act(async () => {
        root.render(
          <div>
            <MockComponent />
          </div>,
        );
      });

      expect(mockMount).toHaveBeenCalledTimes(1);
      expect(mockUpdate).toHaveBeenCalledTimes(0);
      expect(mockUnmount).toHaveBeenCalledTimes(0);

// ... (508 more lines)