Angular: Does all incoming data need to be converted to types?

Question

Angular

Angular 2+.
For example, a JSON array of objects came from the server. Do they need to create Model.ts to describe the type of each field of the object, and then convert each object from JSON to TypeScript types?
And if data comes from the server that is not in the database, for example, the API provides services for calculating any values. How then to work with TypeScript classes?