Today's mission involves using multiple Object-Oriented Programming (OOP) principles to tackle complex tasks in TypeScript. When principles like Encapsulation, Abstraction, Polymorphism, and Composition are integrated, the resulting code becomes streamlined and easier to manage.

Our goal is to dissect two real-world examples, gaining insights into how these principles can seamlessly orchestrate solutions.

Let's design an online library system to reinforce our understanding of Encapsulation and Polymorphism. Encapsulation will help us protect the attributes of books, members, and transactions, ensuring they are accessible in a controlled manner using TypeScript's features. Polymorphism will demonstrate its power by enabling a single interface to represent different underlying forms, such as digital and print versions of books.

In this code snippet, Encapsulation is clearly demonstrated through the class structures and the controlled access to their attributes using TypeScript's private keyword. Polymorphism is vividly illustrated by how both DigitalBook and PhysicalBook classes inherit from the Book class but provide their own implementations of the getBookType method. This setup allows objects of DigitalBook and PhysicalBook to be used interchangeably when a book's type needs to be identified, demonstrating polymorphism's capability to work with objects of different classes through a common interface.

• Encapsulation ensures that details about members and books are well-contained within their respective classes.
• Polymorphism showcases flexibility by treating different book types uniformly, making the system more adaptive and scalable.

Next, we'll develop a shape-drawing application capable of drawing various shapes. For this, we'll employ the principles of Abstraction and Composition.

• Abstraction simplifies the complexity associated with drawing different shapes.
• Composition takes care of composite shapes.

Here's how we translate these principles into our shape-drawing application:

This example unveils how Abstraction streamlines the process of drawing different shapes, and Composition handles complex shapes.

Well done! You combined multiple OOP principles to respond to complex tasks. By dissecting real-world examples, you understood how these principles found their applications in TypeScript. Now, it's time to put this knowledge to work. Practice fortifies concepts, transforming knowledge into expertise. So, let's get coding!