StrictEffectsMode-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';

let React;
let ReactNoop;
let act;

describe('StrictEffectsMode', () => {
  beforeEach(() => {
    jest.resetModules();
    act = require('internal-test-utils').act;

    React = require('react');
    ReactNoop = require('react-noop-renderer');
  });

  // @gate !disableLegacyMode
  it('should not double invoke effects in legacy mode', async () => {
    const log = [];
    function App({text}) {
      React.useEffect(() => {
        log.push('useEffect mount');
        return () => log.push('useEffect unmount');
      });

      React.useLayoutEffect(() => {
        log.push('useLayoutEffect mount');
        return () => log.push('useLayoutEffect unmount');
      });

      return text;
    }

    const root = ReactNoop.createLegacyRoot();
    await act(() => {
      root.render(
        <React.StrictMode>
          <App text={'mount'} />
        </React.StrictMode>,
      );
    });

    expect(log).toEqual(['useLayoutEffect mount', 'useEffect mount']);
  });

  it('double invoking for effects works properly', async () => {
    const log = [];
    function App({text}) {
      React.useEffect(() => {
        log.push('useEffect mount');
        return () => log.push('useEffect unmount');
      });
// ... (908 more lines)