Authenticated API Requests with API Key Header in JavaScript

async function makeAuthenticatedApiRequest(url, apiKey, method = 'GET', data = null) {
  const headers = {
    // Use 'x-api-key' or 'Authorization: Bearer <API_KEY>' as per API documentation
    'Authorization': `Bearer ${apiKey}`,
    'Content-Type': 'application/json' 
  };

  const options = {
    method: method,
    headers: headers,
  };

  if (data) {
    options.body = JSON.stringify(data);
  }

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

    if (!response.ok) {
      // Handle HTTP errors
      const errorData = await response.json().catch(() => ({ message: response.statusText }));
      throw new Error(`API Error: ${response.status} - ${errorData.message}`);
    }

    return await response.json();
  } catch (error) {
    console.error('Failed to make authenticated API request:', error);
    throw error; // Re-throw to allow caller to handle
  }
}

// Example Usage (in a client-side environment or Node.js with a fetch polyfill):
// const API_ENDPOINT = 'https://api.example.com/v1/profile';
// const YOUR_API_KEY = 'your_secret_api_key'; // In client-side, consider proxying to hide key

// Fetch user profile
// makeAuthenticatedApiRequest(API_ENDPOINT, YOUR_API_KEY)
//   .then(profile => console.log('User Profile:', profile))
//   .catch(error => console.error('Error fetching profile:', error));

// // Create a new resource
// const newPost = { title: 'New Post', content: 'Hello API!' };
// makeAuthenticatedApiRequest('https://api.example.com/v1/posts', YOUR_API_KEY, 'POST', newPost)
//   .then(response => console.log('New Post Created:', response))
//   .catch(error => console.error('Error creating post:', error));