Function usePrevious

A React hook that stores the previous value of a variable.

This hook uses a ref to keep track of the previous value of the provided variable. On every update, the current value is stored so that the previous value is accessible.

Example

import React, { useState } from "react";
import { usePrevious } from "essential-hooks-collection";

const MyComponent = () => {
  const [count, setCount] = useState(0);
  const prevCount = usePrevious(count);

  return (
    <div>
      <p>Current count: {count}</p>
      <p>Previous count: {prevCount}</p>
      <button onClick={() => setCount(count + 1)}>Increment</button>
    </div>
  );
};

export default MyComponent;
  • usePrevious<T>(value: T): undefined | T

    Type Parameters

    • T

      The type of the value.

    Parameters

    • value: T

      The current value.

    Returns undefined | T

    The previous value before the last update, or undefined if not available.

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