cloudflare-cors-options.js

// ======================================================
// Handle Options to pass CORS
// ======================================================

const corsHeaders = {
  'Access-Control-Allow-Origin': '*',
  'Access-Control-Allow-Methods': 'GET, HEAD, POST, PUT, OPTIONS',
  'Access-Control-Allow-Headers': 'Content-Type, API_KEY_ID, Authorization',
  'Access-Control-Max-Age': '86400',
}
function handleOptions(request) {
  // Make sure the necessary headers are present
  // for this to be a valid pre-flight request
  if (
    request.headers.get('Origin') !== null &&
    request.headers.get('Access-Control-Request-Method') !== null &&
    request.headers.get('Access-Control-Request-Headers') !== null
  ) {
    // Handle CORS pre-flight request.
    // If you want to check the requested method + headers
    // you can do that here.
    return new Response(null, {
      headers: corsHeaders,
    })
  } else {
    // Handle standard OPTIONS request.
    // If you want to allow other HTTP Methods, you can do that here.
    return new Response(null, {
      headers: {
        Allow: 'GET, HEAD, POST, PUT, OPTIONS',
      },
    })
  }
}