@carbon/react/lib/internal/usePreviousValue.js

React components for the Carbon Design System

/**
 * Copyright IBM Corp. 2016, 2023
 *
 * This source code is licensed under the Apache-2.0 license found in the
 * LICENSE file in the root directory of this source tree.
 */

'use strict';

var React = require('react');

/**
 * Stores the previous value of a given input.
 *
 * @param value - The current value.
 * @returns The value before the current render.
 *
 * @example
 * const [count, setCount] = useState(0);
 * const prevCount = usePreviousValue(count);
 */
const usePreviousValue = value => {
  const ref = React.useRef(undefined);
  React.useEffect(() => {
    ref.current = value;
  }, [value]);
  return ref.current;
};

exports.usePreviousValue = usePreviousValue;