72 строки
1.8 KiB
JavaScript
72 строки
1.8 KiB
JavaScript
/**
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* Copyright (c) Facebook, Inc. and its affiliates.
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*
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* This source code is licensed under the MIT license found in the
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* LICENSE file in the root directory of this source tree.
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*
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* @format
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* @flow
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*/
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'use strict';
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import type {ElementRef, Ref} from 'react';
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type Args = $ReadOnly<{|
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getForwardedRef: () => ?Ref<any>,
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setLocalRef: (ref: ElementRef<any>) => mixed,
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|}>;
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/**
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* This is a helper function for when a component needs to be able to forward a ref
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* to a child component, but still needs to have access to that component as part of
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* its implementation.
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*
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* Its main use case is in wrappers for native components.
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*
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* Usage:
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*
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* class MyView extends React.Component {
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* _nativeRef = null;
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*
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* _setNativeRef = setAndForwardRef({
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* getForwardedRef: () => this.props.forwardedRef,
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* setLocalRef: ref => {
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* this._nativeRef = ref;
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* },
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* });
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*
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* render() {
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* return <View ref={this._setNativeRef} />;
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* }
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* }
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*
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* const MyViewWithRef = React.forwardRef((props, ref) => (
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* <MyView {...props} forwardedRef={ref} />
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* ));
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*
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* module.exports = MyViewWithRef;
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*/
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function setAndForwardRef({
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getForwardedRef,
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setLocalRef,
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}: Args): (ref: ElementRef<any>) => void {
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return function forwardRef(ref: ElementRef<any>) {
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const forwardedRef = getForwardedRef();
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setLocalRef(ref);
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// Forward to user ref prop (if one has been specified)
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if (typeof forwardedRef === 'function') {
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// Handle function-based refs. String-based refs are handled as functions.
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forwardedRef(ref);
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} else if (typeof forwardedRef === 'object' && forwardedRef != null) {
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// Handle createRef-based refs
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forwardedRef.current = ref;
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}
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};
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}
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module.exports = setAndForwardRef;
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