Authenticate API Requests with JWT Bearer Token

async function makeAuthenticatedApiCall(url, method = 'GET', data = null, jwtToken) {
  if (!jwtToken) {
    throw new Error('JWT token is required for authenticated API calls.');
  }

  const headers = {
    'Content-Type': 'application/json',
    'Authorization': `Bearer ${jwtToken}` // Crucial for JWT authentication
  };

  const options = {
    method: method,
    headers: headers,
    body: data ? JSON.stringify(data) : undefined
  };

  try {
    const response = await fetch(url, options);

    if (!response.ok) {
      const errorText = await response.text();
      throw new Error(`API call failed: ${response.status} - ${errorText}`);
    }

    return response.json();
  } catch (error) {
    console.error('Error making authenticated API call:', error);
    throw error;
  }
}

// Example usage (assuming you have a JWT token, e.g., from a login):
// const USER_JWT = 'eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9...'; // Replace with actual JWT
// const API_URL = 'https://api.example.com/protected-data';
//
// (async () => {
//   try {
//     const protectedData = await makeAuthenticatedApiCall(API_URL, 'GET', null, USER_JWT);
//     console.log('Protected data fetched:', protectedData);
//
//     // Example POST request with JWT
//     // const postResult = await makeAuthenticatedApiCall(
//     //   'https://api.example.com/create-item',
//     //   'POST',
//     //   { name: 'New Item', value: 123 },
//     //   USER_JWT
//     // );
//     // console.log('Item created:', postResult);
//   } catch (error) {
//     console.error('Failed to fetch protected data:', error);
//   }
// })();