ReactHooks.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 {Dispatcher} from 'react-reconciler/src/ReactInternalTypes';
import type {
  ReactContext,
  StartTransitionOptions,
  Usable,
  Awaited,
} from 'shared/ReactTypes';
import {REACT_CONSUMER_TYPE} from 'shared/ReactSymbols';

import ReactSharedInternals from 'shared/ReactSharedInternals';

type BasicStateAction<S> = (S => S) | S;
type Dispatch<A> = A => void;

function resolveDispatcher() {
  const dispatcher = ReactSharedInternals.H;
  if (__DEV__) {
    if (dispatcher === null) {
      console.error(
        'Invalid hook call. Hooks can only be called inside of the body of a function component. This could happen for' +
          ' one of the following reasons:\n' +
          '1. You might have mismatching versions of React and the renderer (such as React DOM)\n' +
          '2. You might be breaking the Rules of Hooks\n' +
          '3. You might have more than one copy of React in the same app\n' +
          'See https://react.dev/link/invalid-hook-call for tips about how to debug and fix this problem.',
      );
    }
  }
  // Will result in a null access error if accessed outside render phase. We
  // intentionally don't throw our own error because this is in a hot path.
  // Also helps ensure this is inlined.
  return ((dispatcher: any): Dispatcher);
}

export function getCacheForType<T>(resourceType: () => T): T {
  const dispatcher = ReactSharedInternals.A;
  if (!dispatcher) {
    // If there is no dispatcher, then we treat this as not being cached.
    return resourceType();
  }
  return dispatcher.getCacheForType(resourceType);
}

export function useContext<T>(Context: ReactContext<T>): T {
  const dispatcher = resolveDispatcher();
  if (__DEV__) {
    if (Context.$$typeof === REACT_CONSUMER_TYPE) {
      console.error(
        'Calling useContext(Context.Consumer) is not supported and will cause bugs. ' +
          'Did you mean to call useContext(Context) instead?',
      );
// ... (182 more lines)