Swift SwiftUI

SwiftUI Standards

Priority: P0

Implementation Guidelines

State Management

• @State: Private UI state owned by the view (e.g., toggle, text input).
• @Binding: Two-way connection to parent's @State.
• @ObservedObject: Reference to external observable object.
• @StateObject: View owns the lifecycle of the object.
• @EnvironmentObject: Shared data across view hierarchy.

View Composition

• Extract Subviews: Keep views small (<200 lines). Extract reusable components.
• View Modifiers: Chain modifiers for styling (.font(), .padding()).
• Custom Modifiers: Create ViewModifier for reusable styles.

Performance

• Avoid Heavy Computation: Use @State + .task() for async work.
• Equatable: Conform views to Equatable to prevent unnecessary re-renders.
• LazyStacks: Use LazyVStack/LazyHStack for large lists.

Anti-Patterns

• @ObservedObject Ownership: **No @ObservedObject for owned objects**: Use @StateObject.
• Heavy body: **No logic in body**: Move to computed properties or methods.
• Force Unwrap in Views: **No ! in View**: Use if-let or nil coalescing.

References

• State & Binding