/** * Copyright (c) Facebook, Inc. and its affiliates. * * This source code is licensed under the MIT license found in the * LICENSE file in the root directory of this source tree. * * @format * @flow strict-local */ 'use strict'; import Dimensions from './Dimensions'; import {type DisplayMetrics} from './NativeDeviceInfo'; import {useEffect, useState} from 'react'; export default function useWindowDimensions(): DisplayMetrics { const [dims, setDims] = useState(() => Dimensions.get('window')); useEffect(() => { function handleChange({window}) { setDims(window); } Dimensions.addEventListener('change', handleChange); // We might have missed an update between calling `get` in render and // `addEventListener` in this handler, so we set it here. If there was // no change, React will filter out this update as a no-op. setDims(Dimensions.get('window')); return () => { Dimensions.removeEventListener('change', handleChange); }; }, []); return dims; }