src/hooks/usePrevious.ts

/**
 *
 * Copyright 2023-2024 InspectorRAGet Team
 *
 * Licensed 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 CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 **/

import { useEffect, useRef } from 'react';

/**
 * Returns the value passed to the hook on previous render.
 *
 * Yields `undefined` on first render.
 *
 * @param value Value to yield on next render
 */
export default function usePrevious<T>(value?: T): T | undefined {
  const prev = useRef<T>();

  useEffect(() => {
    prev.current = value;
  });

  return prev.current;
}