ReactFiberAct.old.js

/**
 * Copyright (c) Facebook, Inc. and its affiliates.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 *
 * @flow
 */

import type {Fiber} from './ReactFiber.old';

import ReactSharedInternals from 'shared/ReactSharedInternals';

import {warnsIfNotActing} from './ReactFiberHostConfig';

const {ReactCurrentActQueue} = ReactSharedInternals;

export function isLegacyActEnvironment(fiber: Fiber) {
  if (__DEV__) {
    // Legacy mode. We preserve the behavior of React 17's act. It assumes an
    // act environment whenever `jest` is defined, but you can still turn off
    // spurious warnings by setting IS_REACT_ACT_ENVIRONMENT explicitly
    // to false.

    const isReactActEnvironmentGlobal =
      // $FlowExpectedError – Flow doesn't know about IS_REACT_ACT_ENVIRONMENT global
      typeof IS_REACT_ACT_ENVIRONMENT !== 'undefined'
        ? IS_REACT_ACT_ENVIRONMENT
        : undefined;

    // $FlowExpectedError - Flow doesn't know about jest
    const jestIsDefined = typeof jest !== 'undefined';
    return (
      warnsIfNotActing && jestIsDefined && isReactActEnvironmentGlobal !== false
    );
  }
  return false;
}

export function isConcurrentActEnvironment() {
  if (__DEV__) {
    const isReactActEnvironmentGlobal =
      // $FlowExpectedError – Flow doesn't know about IS_REACT_ACT_ENVIRONMENT global
      typeof IS_REACT_ACT_ENVIRONMENT !== 'undefined'
        ? IS_REACT_ACT_ENVIRONMENT
        : undefined;

    if (!isReactActEnvironmentGlobal && ReactCurrentActQueue.current !== null) {
      // TODO: Include link to relevant documentation page.
      console.error(
        'The current testing environment is not configured to support ' +
          'act(...)',
      );
    }
    return isReactActEnvironmentGlobal;
  }
  return false;
}