GT2/Ejectable/node_modules/react-native/Libraries/Utilities/useWindowDimensions.js

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2021-08-16 00:14:59 +00:00
/**
* 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 [dimensions, setDimensions] = useState(() => Dimensions.get('window'));
useEffect(() => {
function handleChange({window}) {
if (
dimensions.width !== window.width ||
dimensions.height !== window.height ||
dimensions.scale !== window.scale ||
dimensions.fontScale !== window.fontScale
) {
setDimensions(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.
handleChange({window: Dimensions.get('window')});
return () => {
Dimensions.removeEventListener('change', handleChange);
};
}, [dimensions]);
return dimensions;
}