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