SchedulerSetTimeout-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 Scheduler;
let scheduleCallback;
let ImmediatePriority;
let UserBlockingPriority;
let NormalPriority;

describe('SchedulerNoDOM', () => {
  // Scheduler falls back to a naive implementation using setTimeout.
  // This is only meant to be used for testing purposes, like with jest's fake timer API.
  beforeEach(() => {
    jest.resetModules();
    jest.useFakeTimers();
    delete global.setImmediate;
    delete global.MessageChannel;
    jest.unmock('scheduler');

    Scheduler = require('scheduler');
    scheduleCallback = Scheduler.unstable_scheduleCallback;
    UserBlockingPriority = Scheduler.unstable_UserBlockingPriority;
    NormalPriority = Scheduler.unstable_NormalPriority;
  });

  it('runAllTimers flushes all scheduled callbacks', () => {
    const log = [];
    scheduleCallback(NormalPriority, () => {
      log.push('A');
    });
    scheduleCallback(NormalPriority, () => {
      log.push('B');
    });
    scheduleCallback(NormalPriority, () => {
      log.push('C');
    });
    expect(log).toEqual([]);
    jest.runAllTimers();
    expect(log).toEqual(['A', 'B', 'C']);
  });

  it('executes callbacks in order of priority', () => {
    const log = [];

    scheduleCallback(NormalPriority, () => {
      log.push('A');
    });
    scheduleCallback(NormalPriority, () => {
      log.push('B');
    });
    scheduleCallback(UserBlockingPriority, () => {
// ... (70 more lines)