reacthook useRef

React Hook `useRef` is a function that returns a mutable object with a `current` property that can be used to store and access a value across renders. It is similar to creating an instance property on a class component.

The `useRef` hook is used to:

1. Store a value that persists across renders without triggering a re-render.
2. Access the properties of a DOM node or a React component instance.

The most common use case of `useRef` is to access the DOM nodes, such as:

1. Focus an input element
2. Scroll a container
3. Measure the size of an element

Example:

import React, { useRef } from 'react';

function Example() {
  const inputRef = useRef(null);

  const handleClick = () => {
    inputRef.current.focus();
  };

  return (
    <div>
      <input type="text" ref={inputRef} />
      <button onClick={handleClick}>Focus Input</button>
    </div>
  );
}

In the above example, we are using `useRef` to store a reference to the input element, and in the `handleClick` function, we are accessing that reference to call the `focus` method on the input element.