fix(jsonView): simplify promise return

Author: snirs90

src/decorators.ts

@@ -66,9 +66,7 @@ export function JsonView(params?: {}, method?: string): Function {
 
             if (!!result && (typeof result === "object" || typeof result === "function") && typeof result.then === "function") {
                 // If result is an instance of Promise.
-                return result.then((data: any) => {
-                    return transformer(result, params);
-                });
+                return result.then((data: any) => transformer(result, params));
             }
 
             result = transformer(result, params);