Review: Classes and Generics
Learn how TypeScript classes enforce structure and intent through strict typing, initialization, and access control. Understand generics to write reusable, adaptable, and safe logic across contexts. This lesson helps you combine these features to design robust and scalable TypeScript applications.
We'll cover the following...
- Classes: Structure with boundaries
- Initialization: Deliberate and complete
- Access modifiers: Control what’s visible
- Abstract classes: Structure and enforcement
- Generics: Reusable logic, exact types
- Generic type aliases and interfaces: Reusable patterns
- Generic classes: Type-safe containers with behavior
- What was reinforced?
This chapter introduced two of the most expressive features in the language: classes, for modeling structure and behavior with guarantees and generics, for designing reusable logic that stays type-safe across contexts.
Together, they elevate TypeScript from a typed JavaScript helper to a full-scale modeling language for real-world architecture.
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. Fields must be declared and initialized. Behavior must be typed. Constructors must be complete. The compiler ensures nothing is left ambiguous.
class User {constructor(public name: string, private email: string) {}greet(): string {return `Welcome, ${this.name}`;}}
Fields are created and initialized in a single step using parameter properties.
Access modifiers control visibility.
Method return types are explicit and enforced.
This is the structure we can rely on—every time an instance is created. ...