cache.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 {
  ReactContext,
  Thenable,
  FulfilledThenable,
  RejectedThenable,
} from 'shared/ReactTypes';

import * as React from 'react';
import {createContext} from 'react';

// TODO (cache) Remove this cache; it is outdated and will not work with newer APIs like startTransition.

// Cache implementation was forked from the React repo:
// https://github.com/facebook/react/blob/main/packages/react-cache/src/ReactCacheOld.js
//
// This cache is simpler than react-cache in that:
// 1. Individual items don't need to be invalidated.
//    Profiling data is invalidated as a whole.
// 2. We didn't need the added overhead of an LRU cache.
//    The size of this cache is bounded by how many renders were profiled,
//    and it will be fully reset between profiling sessions.

export type {Thenable};

export type Resource<Input, Key, Value> = {
  clear(): void,
  invalidate(Key): void,
  read(Input): Value,
  preload(Input): void,
  write(Key, Value): void,
};

let readContext;
if (typeof React.use === 'function') {
  readContext = function (Context: ReactContext<null>) {
    // eslint-disable-next-line react-hooks-published/rules-of-hooks
    return React.use(Context);
  };
} else if (
  typeof (React: any).__SECRET_INTERNALS_DO_NOT_USE_OR_YOU_WILL_BE_FIRED ===
  'object'
) {
  const ReactCurrentDispatcher = (React: any)
    .__SECRET_INTERNALS_DO_NOT_USE_OR_YOU_WILL_BE_FIRED.ReactCurrentDispatcher;
  readContext = function (Context: ReactContext<null>) {
    const dispatcher = ReactCurrentDispatcher.current;
    if (dispatcher === null) {
      throw new Error(
        'react-cache: read and preload may only be called from within a ' +
          "component's render. They are not supported in event handlers or " +
          'lifecycle methods.',
// ... (132 more lines)