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1/*
2 * Copyright 2023 Adobe. All rights reserved.
3 * This file is licensed to you under the Apache License, Version 2.0 (the "License");
4 * you may not use this file except in compliance with the License. You may obtain a copy
5 * of the License at http://www.apache.org/licenses/LICENSE-2.0
6 *
7 * Unless required by applicable law or agreed to in writing, software distributed under
8 * the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR REPRESENTATIONS
9 * OF ANY KIND, either express or implied. See the License for the specific language
10 * governing permissions and limitations under the License.
11 */
12
13/* eslint-disable rulesdir/pure-render */
14
15import {useRef} from 'react';
16
17export function useDeepMemo<T>(value: T, isEqual: (a: T, b: T) => boolean): T {
18 // Using a ref during render is ok here because it's only an optimization – both values are equivalent.
19 // If a render is thrown away, it'll still work the same no matter if the next render is the same or not.
20 let lastValue = useRef<T | null>(null);
21 if (value && lastValue.current && isEqual(value, lastValue.current)) {
22 value = lastValue.current;
23 }
24
25 lastValue.current = value;
26 return value;
27}