Certainly! Here's the modified code that returns the `base64data` from the function:

```javascript
// Function to fetch audio from URL and convert it to base64
async function fetchAndConvertToBase64(url) {
  try {
    const response = await fetch(url);
    const audioBlob = await response.blob();

    const reader = new FileReader();
    reader.readAsDataURL(audioBlob);
    return new Promise((resolve, reject) => {
      reader.onloadend = function () {
        const base64data = reader.result.split(',')[1]; // Extract base64 data
        resolve(base64data);
      };
    });
  } catch (error) {
    console.error('Error fetching or converting audio to base64:', error);
    return null;
  }
}

// Example usage:
const audioURL = 'YOUR_AUDIO_URL_HERE';
fetchAndConvertToBase64(audioURL)
  .then(base64data => {
    if (base64data) {
      // Use the base64 data here as needed
      console.log('Base64 data:', base64data);
      // Call function to play audio using Audio5js or perform other actions
      // playAudioUsingAudio5js(base64data);
    } else {
      console.error('No base64 data available.');
    }
  });
```

This updated function `fetchAndConvertToBase64()` now returns a Promise that resolves with the `base64data` of the fetched audio. You can use this function and handle the returned `base64data` accordingly in your application, such as playing it using Audio5js or performing any other necessary actions.