Review: Classes and Generics

Review how TypeScript’s class system and generics enforce safety, enable reuse, and bring clarity to object-oriented and parametric design.

This chapter introduced two of the most expressive features in the language: classes, for modeling structure and behavior with TypeScript guarantees, and generics, for designing reusable logic that stays type-safe across contexts.

Together, they elevate TypeScript from a powerful tool for modeling application structure with static types.

Let’s review what we made possible.

Classes: Structure with boundaries

In TypeScript, a class is more than a shape—it’s a set of guarantees. In strict mode, TypeScript can require fields to be initialized before use, and it types behavior and constructor signatures to catch mistakes early. The compiler ensures nothing is left ambiguous.