Add error handling to the frontend

lib/error-handler.js

@@ -0,0 +1,39 @@
+import debuglog from 'debug';
+
+const debug = debuglog('match.audio');
+
+export default function () {
+  return function* error(next) {
+    this.set('Server', 'Nintendo 64');
+    try {
+      yield next;
+    } catch (err) {
+      if (err.status === 404) {
+        this.body = '404 Page Not Found';
+      } else if (err.status >= 400 && err.status < 500) {
+        this.status = err.status;
+        this.body = err.error;
+      } else {
+        debug('Error: %o', err);
+        throw err;
+      }
+    }
+
+    if (this.status !== 404) return;
+
+    switch (this.accepts('html', 'json')) {
+      case 'html':
+        this.type = 'html';
+        this.body = '404 Page Not Found';
+        break;
+      case 'json':
+        this.body = {
+          message: 'Page Not Found',
+        };
+        break;
+      default:
+        this.type = 'text';
+        this.body = 'Page Not Found';
+    }
+  };
+}