Add asyncController

app/src/api/routes/asyncController.ts

@@ -0,0 +1,17 @@
+import { Request, Response, NextFunction } from 'express';
+
+/**
+ * A wrapper for controller functions that return a Promise, enabling them to be used with Express
+ * Without this wrapper, Promise rejections caused by an error in the controller will not be passed properly
+ * to subsequent middleware layers.
+ * @param fn the async controller function to be wrapped
+ * @returns controller function which handles async errors correctly
+ */
+function asyncController(fn: (req: Request, res: Response, next: NextFunction) => Promise<any>) {
+    return (req: Request, res: Response, next: NextFunction) => {
+        Promise.resolve(fn(req, res, next))
+            .catch(next);
+    };
+}
+
+export default asyncController;