How does SwiftUI renders view

SwiftUI renders views by using a declarative approach. In SwiftUI, views are descriptions of what the current state of the UI should be, rather than long-lived object instances that receive imperative commands over time. This is why SwiftUI views are value types defined using structs instead of classes. SwiftUI takes these descriptions and creates an efficient data structure to represent them, maintaining this data structure behind the scenes. This structure is used to produce different outputs, such as what's shown on screen, the gestures and interactive aspects of the view, and its accessibility representation.

SwiftUI views are also state-driven. When the state of a view changes, SwiftUI automatically updates the UI, eliminating boilerplate code and reducing update bugs. As data changes, new view values are created and given to SwiftUI, which uses these values to determine how to update its outputs.

Additionally, SwiftUI supports composition, allowing you to break up one view into multiple components without hurting performance. This compositional nature means you can organize your code in a way that makes sense for your app without compromising on performance.

For more details, you can refer to the session SwiftUI essentials (04:30).