/* * Copyright 2023 Adobe. All rights reserved. * This file is licensed to you under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. You may obtain a copy * of the License at http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software distributed under * the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR REPRESENTATIONS * OF ANY KIND, either express or implied. See the License for the specific language * governing permissions and limitations under the License. */ /* eslint-disable rulesdir/pure-render */ import {useRef} from 'react'; export function useDeepMemo(value: T, isEqual: (a: T, b: T) => boolean): T { // Using a ref during render is ok here because it's only an optimization – both values are equivalent. // If a render is thrown away, it'll still work the same no matter if the next render is the same or not. let lastValue = useRef(null); if (value && lastValue.current && isEqual(value, lastValue.current)) { value = lastValue.current; } lastValue.current = value; return value; }