ReactFreshRuntime.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 {FiberRoot} from 'react-reconciler/src/ReactInternalTypes';
import type {
  Family,
  RefreshUpdate,
  ScheduleRefresh,
  ScheduleRoot,
  SetRefreshHandler,
} from 'react-reconciler/src/ReactFiberHotReloading';
import type {ReactNodeList} from 'shared/ReactTypes';

import {REACT_MEMO_TYPE, REACT_FORWARD_REF_TYPE} from 'shared/ReactSymbols';

type Signature = {
  ownKey: string,
  forceReset: boolean,
  fullKey: string | null, // Contains keys of nested Hooks. Computed lazily.
  getCustomHooks: () => Array<Function>,
};

type RendererHelpers = {
  scheduleRefresh: ScheduleRefresh,
  scheduleRoot: ScheduleRoot,
  setRefreshHandler: SetRefreshHandler,
};

if (!__DEV__) {
  throw new Error(
    'React Refresh runtime should not be included in the production bundle.',
  );
}

// In old environments, we'll leak previous types after every edit.
const PossiblyWeakMap = typeof WeakMap === 'function' ? WeakMap : Map;

// We never remove these associations.
// It's OK to reference families, but use WeakMap/Set for types.
const allFamiliesByID: Map<string, Family> = new Map();
const allFamiliesByType: WeakMap<any, Family> | Map<any, Family> =
  new PossiblyWeakMap();
const allSignaturesByType: WeakMap<any, Signature> | Map<any, Signature> =
  new PossiblyWeakMap();
// This WeakMap is read by React, so we only put families
// that have actually been edited here. This keeps checks fast.
const updatedFamiliesByType: WeakMap<any, Family> | Map<any, Family> =
  new PossiblyWeakMap();

// This is cleared on every performReactRefresh() call.
// It is an array of [Family, NextType] tuples.
let pendingUpdates: Array<[Family, any]> = [];

// This is injected by the renderer via DevTools global hook.
// ... (651 more lines)