replace 4xx and 5xx with _error, per 0.14

routes/blog/[slug].html

@@ -46,14 +46,17 @@
 
 <script>
 	export default {
-		preload({ params, query }) {
-			// the `slug` parameter is available because this file
-			// is called [slug].html
-			const { slug } = params;
+		async preload({ params, query }) {
+			// the `slug` parameter is available because
+			// this file is called [slug].html
+			const res = await this.fetch(`blog/${params.slug}.json`);
+			const data = await res.json();
 
-			return this.fetch(`blog/${slug}.json`).then(r => r.json()).then(post => {
-				return { post };
-			});
+			if (res.status === 200) {
+				return { post: data };
+			} else {
+				this.error(res.status, data.message);
+			}
 		}
 	};
 </script>

routes/blog/[slug].json.js

@@ -6,8 +6,8 @@ posts.forEach(post => {
 });
 
 export function get(req, res, next) {
-	// the `slug` parameter is available because this file
-	// is called [slug].json.js
+	// the `slug` parameter is available because
+	// this file is called [slug].json.js
 	const { slug } = req.params;
 
 	if (lookup.has(slug)) {
@@ -17,6 +17,12 @@ export function get(req, res, next) {
 
 		res.end(lookup.get(slug));
 	} else {
-		next();
+		res.writeHead(404, {
+			'Content-Type': 'application/json'
+		});
+
+		res.end(JSON.stringify({
+			message: `Not found`
+		}));
 	}
 }