Signal-Desktop/ts/util/refMerger.ts

36 lines
1.3 KiB
TypeScript

// Copyright 2021 Signal Messenger, LLC
// SPDX-License-Identifier: AGPL-3.0-only
import type { MutableRefObject, Ref } from 'react';
import memoizee from 'memoizee';
/**
* Merges multiple refs.
*
* Returns a new function each time, which may cause unnecessary re-renders. Try
* `createRefMerger` if you want to cache the function.
*/
export function refMerger<T>(
...refs: Array<Ref<unknown>>
): (topLevelRef: T) => void {
return (el: T) => {
refs.forEach(ref => {
// This is a simplified version of [what React does][0] to set a ref.
// [0]: https://github.com/facebook/react/blob/29b7b775f2ecf878eaf605be959d959030598b07/packages/react-reconciler/src/ReactFiberCommitWork.js#L661-L677
if (typeof ref === 'function') {
ref(el);
} else if (ref) {
// I believe the types for `ref` are wrong in this case, as `ref.current` should
// not be `readonly`. That's why we do this cast. See [the React source][1].
// [1]: https://github.com/facebook/react/blob/29b7b775f2ecf878eaf605be959d959030598b07/packages/shared/ReactTypes.js#L78-L80
// eslint-disable-next-line no-param-reassign
(ref as MutableRefObject<T>).current = el;
}
});
};
}
export function createRefMerger(): typeof refMerger {
return memoizee(refMerger, { length: false, max: 1 });
}