| 1 | /** |
| 2 | * Copyright (c) Meta Platforms, Inc. and affiliates. |
| 3 | * |
| 4 | * This source code is licensed under the MIT license found in the |
| 5 | * LICENSE file in the root directory of this source tree. |
| 6 | * |
| 7 | * @flow |
| 8 | */ |
| 9 | |
| 10 | export function useSyncExternalStore<T>( |
| 11 | subscribe: (() => void) => () => void, |
| 12 | getSnapshot: () => T, |
| 13 | getServerSnapshot?: () => T, |
| 14 | ): T { |
| 15 | // Note: The shim does not use getServerSnapshot, because pre-18 versions of |
| 16 | // React do not expose a way to check if we're hydrating. So users of the shim |
| 17 | // will need to track that themselves and return the correct value |
| 18 | // from `getSnapshot`. |
| 19 | return getSnapshot(); |
| 20 | } |