react/packages/react-reconciler/src/ReactFiberDevToolsHook.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';
import type {FiberRoot} from './ReactFiberRoot';

import warningWithoutStack from 'shared/warningWithoutStack';

declare var __REACT_DEVTOOLS_GLOBAL_HOOK__: Object | void;

let onCommitFiberRoot = null;
let onCommitFiberUnmount = null;
let hasLoggedError = false;

function catchErrors(fn) {
  return function(arg) {
    try {
      return fn(arg);
    } catch (err) {
      if (__DEV__ && !hasLoggedError) {
        hasLoggedError = true;
        warningWithoutStack(
          false,
          'React DevTools encountered an error: %s',
          err,
        );
      }
    }
  };
}

export const isDevToolsPresent =
  typeof __REACT_DEVTOOLS_GLOBAL_HOOK__ !== 'undefined';

export function injectInternals(internals: Object): boolean {
  if (typeof __REACT_DEVTOOLS_GLOBAL_HOOK__ === 'undefined') {
    // No DevTools
    return false;
  }
  const hook = __REACT_DEVTOOLS_GLOBAL_HOOK__;
  if (hook.isDisabled) {
    // This isn't a real property on the hook, but it can be set to opt out
    // of DevTools integration and associated warnings and logs.
    // https://github.com/facebook/react/issues/3877
    return true;
  }
  if (!hook.supportsFiber) {
    if (__DEV__) {
      warningWithoutStack(
        false,
        'The installed version of React DevTools is too old and will not work ' +
          'with the current version of React. Please update React DevTools. ' +
          'https://fb.me/react-devtools',
      );
    }
    // DevTools exists, even though it doesn't support Fiber.
    return true;
  }
  try {
    const rendererID = hook.inject(internals);
    // We have successfully injected, so now it is safe to set up hooks.
    onCommitFiberRoot = catchErrors(root =>
      hook.onCommitFiberRoot(rendererID, root),
    );
    onCommitFiberUnmount = catchErrors(fiber =>
      hook.onCommitFiberUnmount(rendererID, fiber),
    );
  } catch (err) {
    // Catch all errors because it is unsafe to throw during initialization.
    if (__DEV__) {
      warningWithoutStack(
        false,
        'React DevTools encountered an error: %s.',
        err,
      );
    }
  }
  // DevTools exists
  return true;
}

export function onCommitRoot(root: FiberRoot) {
  if (typeof onCommitFiberRoot === 'function') {
    onCommitFiberRoot(root);
  }
}

export function onCommitUnmount(fiber: Fiber) {
  if (typeof onCommitFiberUnmount === 'function') {
    onCommitFiberUnmount(fiber);
  }
}