Agent-Skills.md

Agent Skills: SwiftUI Expert

Build declarative UI and manage data flow with SwiftUI in iOS. Use when building declarative SwiftUI views or managing data flow with property wrappers. (triggers: **/*View.swift, View, State, Binding, EnvironmentObject)

UncategorizedID: hoangnguyen0403/agent-skills-standard/ios-swiftui

Repository

hoangnguyen0403/agent-skills-standard
HoangNguyen0403License: Apache-2.0
362103

Install this agent skill to your local

pnpm dlx add-skill https://github.com/HoangNguyen0403/agent-skills-standard/tree/HEAD/skills/ios/ios-swiftui

Skill Files

Browse the full folder contents for ios-swiftui.

Download Skill

Loading file tree…

skills/ios/ios-swiftui/SKILL.md

Skill Metadata

Name
ios-swiftui
Description
Build declarative UI and manage data flow with SwiftUI in iOS. Use when building declarative SwiftUI views or managing data flow with property wrappers.

SwiftUI Expert

Priority: P0 (CRITICAL)

Role: iOS UI Expert. Prioritize smooth 60fps, clean data flow.

Implementation Guidelines

  • Views: Small, composable structs. Extract subviews often to keep body clean.
  • State Selection (iOS 17+, default):
  • @State for local simple data (Booleans, Strings, local view toggles).
  • @State for VMs marked @Observable (owning parent creates it once: @State private var vm = MyViewModel()).
  • Plain let/property for passed-in @Observable VMs — no wrapper needed, child views auto-track only the fields they read.
  • Legacy (pre-iOS 17 or Combine ObservableObject VMs):
  • @StateObject for VMs (initialized only once in parent view).
  • @ObservedObject for passed-in VMs (initialized by parent).
  • Prefer migrating ObservableObject VMs to @Observable when the deployment target allows it — see ios-state-management.
  • Modifiers: Order matters sequentially. Apply layout modifiers before visual ones (e.g., .padding().background()).
  • Preview: Always provide PreviewProvider or #Preview for every view.

Verification Checklist (Mandatory)

  • [ ] Body Property: body property computationally cheap? (No complex logic or calculations).
  • [ ] State Flow: @State/@StateObject VM initialized only once (in parent)?
  • [ ] Identity: Lists/ForEach stable id?
  • [ ] Main Actor: UI updates strictly on Main Actor?

Anti-Patterns

  • No Logic in Body: Move calculations to ViewModel or computed vars. Keep body for UI composition only.
  • No ObservedObject Init: NOT init @ObservedObject inside View settings — this causes leaks and performance issues.
  • No New ObservableObject VMs on iOS 17+: Use @Observable for new code; reserve ObservableObject/@Published for code that must support pre-17 or already depends on Combine operators.
  • No Hardcoded Sizes: Use flexible frames and spacers for responsive UI.

Canonical response anchors

When this skill applies, preserve the following domain terminology or equivalent concrete examples in the answer when relevant:

  • @State for local simple data