如何使用TypeScript在Angular 2中正确地将对象转换为JSON

I'm creating an Angular 2 simple CRUD application that allows me to CRUD products. I'm trying to implement the post method so I can create a product. My backend is an ASP.NET Web API. I'm having some trouble because when transforming my Product object to JSON it is not doing it correctly. The expected JSON should be like this:I'm creating an Angular 2 simple CRUD applicati