treat foo/index.json.js as foo.json.js - fixes #297

test/app/routes/blog/index.json.js

@@ -0,0 +1,17 @@
+import posts from './_posts.js';
+
+const contents = JSON.stringify(posts.map(post => {
+	return {
+		title: post.title,
+		slug: post.slug
+	};
+}));
+
+export function get(req, res) {
+	res.writeHead(200, {
+		'Content-Type': 'application/json',
+		'Cache-Control': `max-age=${30 * 60 * 1e3}` // cache for 30 minutes
+	});
+
+	res.end(contents);
+}