ReactDefaultTransitionIndicator-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
 * @jest-environment node
 */

'use strict';

let React;
let ReactNoop;
let Scheduler;
let act;
let use;
let useOptimistic;
let useState;
let useTransition;
let useDeferredValue;
let assertLog;
let waitForPaint;

describe('ReactDefaultTransitionIndicator', () => {
  beforeEach(() => {
    jest.resetModules();

    React = require('react');
    ReactNoop = require('react-noop-renderer');
    Scheduler = require('scheduler');
    const InternalTestUtils = require('internal-test-utils');
    act = InternalTestUtils.act;
    assertLog = InternalTestUtils.assertLog;
    waitForPaint = InternalTestUtils.waitForPaint;
    use = React.use;
    useOptimistic = React.useOptimistic;
    useState = React.useState;
    useTransition = React.useTransition;
    useDeferredValue = React.useDeferredValue;
  });

  // @gate enableDefaultTransitionIndicator
  it('triggers the default indicator while a transition is on-going', async () => {
    let resolve;
    const promise = new Promise(r => (resolve = r));
    function App() {
      return use(promise);
    }

    const root = ReactNoop.createRoot({
      onDefaultTransitionIndicator() {
        Scheduler.log('start');
        return () => {
          Scheduler.log('stop');
        };
      },
    });
    await act(() => {
      React.startTransition(() => {
// ... (421 more lines)