Merge pull request #479 from tokuhirom/typescript5

Upgrade TypeScript to version 5!

Author: tokuhirom

package-lock.json

@@ -55,7 +55,7 @@
     "nyc": "15.1.0",
     "prettier": "3.0.3",
     "ts-node": "10.9.1",
-    "typescript": "3.9.10",
+    "typescript": "5.2.2",
     "vuepress": "1.9.10"
   },
   "husky": {

package.json

@@ -76,16 +76,16 @@ function listen(port: number, middleware?: express.RequestHandler) {
   );
 
   return new Promise(resolve => {
-    server = app.listen(port, () => resolve());
+    server = app.listen(port, () => resolve(undefined));
   });
 }
 
 function close() {
   return new Promise(resolve => {
     if (!server) {
-      resolve();
+      resolve(undefined);
     }
-    server.close(() => resolve());
+    server.close(() => resolve(undefined));
   });
 }