What NavigationView limitations did NavigationStack solve for programmatic navigation?

WHAT THIS TESTS: Whether you recognize that NavigationView's API was architecturally mismatched for modern SwiftUI data flow. Interviewers want to hear that you have felt the pain of scattered isActive booleans, understand why multi-layer programmatic pushes were fragile, and know that NavigationStack replaces implicit state with an explicit array-based path.

A GOOD ANSWER COVERS: First, the state scattering problem. In NavigationView, each NavigationLink relied on an isActive binding or tag-selection patterns, which meant navigation state lived inside individual views rather than in a single source of truth. Second, the same-type limitation. Because NavigationLink destinations were tied to view identity, pushing two screens of the same type required wrapping views in AnyView or using opaque hacks that broke animations and state restoration. Third, programmatic friction. Moving to a specific route meant toggling the correct Boolean chain or managing a complex selection binding, rather than simply mutating a stack. Fourth, the NavigationStack solution. It introduces a path value, either a typed array or NavigationPath, that acts as the route stack. You append to push, popLast to pop, and assign an array to restore or deep link. NavigationLink(value:) and navigationDestination(for:) separate the trigger from the destination, making the stack fully data-driven.

COMMON WRONG ANSWERS: Calling NavigationStack a visual or naming update with no behavioral change. Describing the limitation as merely needing more boilerplate without explaining why the state model was broken. Suggesting that NavigationView could not do programmatic navigation at all; it could, but the mechanism was indirect and fragile. Failing to mention the path array or the deep-linking implications.

LIKELY FOLLOW-UPS: How would you implement deep linking into a third-level screen using NavigationStack? When would you use NavigationPath versus a typed array like [Route]? How do you handle navigation state in redux-like or MVVM architectures with NavigationStack? What happens to the path when the user triggers a system back gesture?

ONE CONCRETE EXAMPLE: Imagine a product catalog where tapping a product pushes a detail view, and tapping a related item pushes another detail view of the same type. In NavigationView, two NavigationLinks pointing to the same ProductDetail type would conflict or require AnyView wrappers. In NavigationStack, you define navigationDestination(for: Product.self) and append a Product ID to the path array. Pushing three related products is just path.append(productA), path.append(productB), path.append(productC). To deep link, deserialize a URL into [Product] and assign it to the path on launch.