backendManager.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.
 *
 * @flow
 */

import type {
  DevToolsHook,
  ReactRenderer,
} from 'react-devtools-shared/src/backend/types';
import {hasAssignedBackend} from 'react-devtools-shared/src/backend/utils';
import {COMPACT_VERSION_NAME} from 'react-devtools-extensions/src/utils';
import {getIsReloadAndProfileSupported} from 'react-devtools-shared/src/utils';
import {
  getIfReloadedAndProfiling,
  onReloadAndProfile,
  onReloadAndProfileFlagsReset,
} from 'react-devtools-shared/src/utils';

let welcomeHasInitialized = false;
const requiredBackends = new Set<string>();

function welcome(event: $FlowFixMe) {
  if (
    event.source !== window ||
    event.data.source !== 'react-devtools-content-script'
  ) {
    return;
  }

  // In some circumstances, this method is called more than once for a single welcome message.
  // The exact circumstances of this are unclear, though it seems related to 3rd party event batching code.
  //
  // Regardless, call this method multiple times can cause DevTools to add duplicate elements to the Store
  // (and throw an error) or worse yet, choke up entirely and freeze the browser.
  //
  // The simplest solution is to ignore the duplicate events.
  // To be clear, this SHOULD NOT BE NECESSARY, since we remove the event handler below.
  //
  // See https://github.com/facebook/react/issues/24162
  if (welcomeHasInitialized) {
    console.warn(
      'React DevTools detected duplicate welcome "message" events from the content script.',
    );
    return;
  }

  welcomeHasInitialized = true;

  window.removeEventListener('message', welcome);

  setup(window.__REACT_DEVTOOLS_GLOBAL_HOOK__);
}

function setup(hook: ?DevToolsHook) {
  // this should not happen, but Chrome can be weird sometimes
  if (hook == null) {
// ... (151 more lines)