// Need to create a new RandOnce component based on the Rand component, // which when used in App // will not update the random number every 3 seconds, but will output a random number only once. // const Rand = () => <span>{Math.random()}</span>

To make the RandOnce component display a random number only once during the initial render and not update every 3 seconds, you can use the useState or useMemo hook to generate the number just once.

Example implementation:

import React, { useState } from 'react';

const RandOnce = () => {
  const [random] = useState(() => Math.random());
  return <span>{random}</span>;
};

// Usage in App
const App = () => {
  return <RandOnce />;
};

Here, useState with an initialization function ensures that Math.random() is called only once when the component mounts, and the value is preserved on subsequent renders.

If the original Rand component updates the number every 3 seconds via a timer, then RandOnce simply does not set such a timer and keeps the number constant.