Handle null body when detecting async iterator

Author: jesseskinner

packages/kit/src/runtime/server/endpoint.js

@@ -60,7 +60,7 @@ export async function render_endpoint(request, route, match) {
 	let normalized_body;
 
 	// ensure the body is an object
-	if (typeof body === 'object' && typeof body[Symbol.asyncIterator] === 'function') {
+	if (body && typeof body === 'object' && typeof body[Symbol.asyncIterator] === 'function') {
 		normalized_body = /** @type {object} */ (body);
 	} else if (
 		(typeof body === 'object' || typeof body === 'undefined') &&