Objects and Classes
TS Classes
Creating TypeScript Classes
TypeScript classes add typed properties and methods with access modifiers.
Introduction to TypeScript Classes
TypeScript classes are a blueprint for creating objects with typed properties, methods, and access control. They enable structured and maintainable code by enforcing typing and providing encapsulation via access modifiers. In this guide, we explore the key features of TypeScript classes, enhancing your ability to write robust applications.
Defining a Basic Class
At the core of TypeScript classes is the ability to define a template for creating objects. Here's how you can define a basic class:
In this example, the Person class has two properties: name and age. The constructor initializes these properties, and the greet method outputs a greeting message.
Type Annotations in Classes
TypeScript enhances JavaScript classes with type annotations, ensuring that each property and method parameter has a defined type. This helps catch errors during development:
The Car class uses type annotations to define the make, model, and year properties as strings and a number, respectively. This type safety is a core advantage of using TypeScript.
Access Modifiers: public, private, and protected
Access modifiers in TypeScript control the visibility of class members. By default, all properties and methods are public. You can use private and protected to restrict access:
In the BankAccount class, the balance property is marked as private, meaning it can only be accessed within the class. The deposit and getBalance methods allow controlled interaction with the balance.
Implementing Interfaces with Classes
TypeScript classes can implement interfaces to ensure that a class adheres to a specific contract. This promotes consistency and reliability:
Both Circle and Square classes implement the Drawable interface, ensuring they both have a draw method. This pattern benefits large applications where consistency across multiple class implementations is crucial.
Conclusion and Next Steps
TypeScript classes provide a powerful mechanism for building scalable and maintainable applications. Understanding how to define and use classes with type annotations and access modifiers is essential for leveraging TypeScript's full potential. In the next post, we'll explore Inheritance in TypeScript, a key concept for creating complex class hierarchies.
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