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- import * as React from 'react';
- import { assignRef } from './assignRef';
- import { useCallbackRef } from './useRef';
- const currentValues = new WeakMap();
- /**
- * Merges two or more refs together providing a single interface to set their value
- * @param {RefObject|Ref} refs
- * @returns {MutableRefObject} - a new ref, which translates all changes to {refs}
- *
- * @see {@link mergeRefs} a version without buit-in memoization
- * @see https://github.com/theKashey/use-callback-ref#usemergerefs
- * @example
- * const Component = React.forwardRef((props, ref) => {
- * const ownRef = useRef();
- * const domRef = useMergeRefs([ref, ownRef]); // 👈 merge together
- * return <div ref={domRef}>...</div>
- * }
- */
- export function useMergeRefs(refs, defaultValue) {
- const callbackRef = useCallbackRef(defaultValue || null, (newValue) => refs.forEach((ref) => assignRef(ref, newValue)));
- // handle refs changes - added or removed
- React.useLayoutEffect(() => {
- const oldValue = currentValues.get(callbackRef);
- if (oldValue) {
- const prevRefs = new Set(oldValue);
- const nextRefs = new Set(refs);
- const current = callbackRef.current;
- prevRefs.forEach((ref) => {
- if (!nextRefs.has(ref)) {
- assignRef(ref, null);
- }
- });
- nextRefs.forEach((ref) => {
- if (!prevRefs.has(ref)) {
- assignRef(ref, current);
- }
- });
- }
- currentValues.set(callbackRef, refs);
- }, [refs]);
- return callbackRef;
- }
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