swift

In Swift, property observers (`willSet` and `didSet`) provide a mechanism to intercept and respond to changes in a property’s value. This functionality allows developers to manage data updates, synchronize UI elements, enforce data validation, and implement custom logic tied to specific property modifications. For example, consider a `totalPrice` property. A `didSet` observer could automatically update a display label whenever the `totalPrice` is recalculated. This approach separates the core logic of calculating the total from the side effect of updating the user interface.

This ability to react to value changes simplifies code by centralizing related actions and reducing the need for scattered update logic. It contributes to a more maintainable and robust codebase, especially in complex applications with intricate data dependencies. Historically, managing side effects related to property changes required more verbose and less elegant solutions. Property observers, introduced in Swift, provide a cleaner, more declarative way to handle these scenarios, improving code readability and reducing the risk of errors. They streamline state management and ensure data consistency across an application.

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