Application classes

• Explain the difference between page logic and application logic.
• Explain how reusable business behaviour should move into classes.

Common types of classes

• Services.
• Use-case classes.
• Domain entities.
• Repositories or data access helpers.
• Value objects.

How Page Logic should use them

• Keep page logic thin.
• Let classes own business rules and workflow decisions.
• Bind only the final output data in page logic.

Keeping code framework-agnostic

• Encourage writing classes that are not tightly coupled to WebEngine.
• Explain how this improves portability and testing.

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Next we'll learn about the client-side build system.