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packages/react-native/Libraries/Utilities/useRefEffect.js
45 строк
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Ruslan Lesiutin
| RN Monorepo | Migrate to package (#36434)
17 мар 2023, 15:03
17 мар 2023, 15:03
714b502
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/** * 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 strict * @format */ import {useCallback, useRef} from 'react'; type CallbackRef<T> = T => mixed; /** * Constructs a callback ref that provides similar semantics as `useEffect`. The * supplied `effect` callback will be called with non-null component instances. * The `effect` callback can also optionally return a cleanup function. * * When a component is updated or unmounted, the cleanup function is called. The * `effect` callback will then be called again, if applicable. * * When a new `effect` callback is supplied, the previously returned cleanup * function will be called before the new `effect` callback is called with the * same instance. * * WARNING: The `effect` callback should be stable (e.g. using `useCallback`). */ export default function useRefEffect<TInstance>( effect: TInstance => (() => void) | void, ): CallbackRef<TInstance | null> { const cleanupRef = useRef<(() => void) | void>(undefined); return useCallback( (instance: null | TInstance) => { if (cleanupRef.current) { cleanupRef.current(); cleanupRef.current = undefined; } if (instance != null) { cleanupRef.current = effect(instance); } }, [effect], ); }