react-native/Libraries/Components/StaticContainer.react.js

55 lines
1.3 KiB
JavaScript

/**
* 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';
const React = require('React');
/**
* Renders static content efficiently by allowing React to short-circuit the
* reconciliation process. This component should be used when you know that a
* subtree of components will never need to be updated.
*
* const someValue = ...; // We know for certain this value will never change.
* return (
* <StaticContainer>
* <MyComponent value={someValue} />
* </StaticContainer>
* );
*
* Typically, you will not need to use this component and should opt for normal
* React reconciliation.
*/
type Props = $ReadOnly<{|
/**
* Whether or not this component should update.
*/
shouldUpdate: ?boolean,
/**
* Content short-circuited by React reconciliation process.
*/
children: React.Node,
|}>;
class StaticContainer extends React.Component<Props> {
shouldComponentUpdate(nextProps: Props): boolean {
return !!nextProps.shouldUpdate;
}
render() {
const child = this.props.children;
return child === null || child === false
? null
: React.Children.only(child);
}
}
module.exports = StaticContainer;