Over my last few years working on production JavaScript apps, I’ve noticed a concerning yet common pattern: first-class models aren’t made explicit. By “first-class models” I mean the primary entities that encompass most of your app’s data. For example, a bookstore inventory system would probably have entities like Books, Authors, and maybe Customers. The inventory system’s primary goals are to display and allow a user to interact with those models. Despite the importance of models like these, I’ve rarely seen them made explicit in frontend apps. Most apps I’ve worked in have code that looks kind of like this: