modernizing-swiftui-api

name	modernizing-swiftui-api
description	Updates SwiftUI code from deprecated and legacy APIs to modern equivalents (iOS 17+ / iOS 26). Covers foregroundStyle, Tab API, onChange, GeometryReader alternatives, sensoryFeedback, @Entry macro, modern overlay/toolbar placements, and more. Use when modernizing existing SwiftUI codebases or reviewing for deprecated API usage.

Modernizing SwiftUI API

Target Swift 6.2+ and iOS 26 as the default. Replace deprecated and legacy patterns with modern equivalents.

High-frequency replacements

Legacy	Modern
foregroundColor(.red)	foregroundStyle(.red)
cornerRadius(8)	clipShape(.rect(cornerRadius: 8))
tabItem { Label(...) }	Tab("Home", systemImage: "house", value: .home) { ... }
.navigationBarLeading / .navigationBarTrailing	.topBarLeading / .topBarTrailing
.overlay(SomeView(), alignment: .top)	.overlay(alignment: .top) { SomeView() }
showsIndicators: false in ScrollView init	.scrollIndicators(.hidden)
UIImpactFeedbackGenerator	.sensoryFeedback(.impact, trigger: value)
Image("avatar")	Image(.avatar) (generated symbol asset API)
PreviewProvider	#Preview { ... }

onChange

Never use the 1-parameter onChange() variant. Use either the zero- or two-parameter form:

// Good
.onChange(of: score) { oldValue, newValue in ... }
.onChange(of: score) { ... }

Custom environment / focus / container values

Use the @Entry macro instead of manually conforming to EnvironmentKey:

extension EnvironmentValues {
    @Entry var theme: Theme = .light
}

GeometryReader

Don't reach for GeometryReader first. Prefer:

• containerRelativeFrame(...) for sizing relative to a scroll container.
• visualEffect { content, proxy in ... } for visual transforms based on layout.
• The Layout protocol for custom layouts.

Flag GeometryReader and suggest the modern alternative.

WebView

When targeting iOS 26+, SwiftUI has a native WebView that replaces almost all WKWebView wrappers in UIViewRepresentable. Add import WebKit.

Shapes and strokes

Fill and stroke can both be chained directly — the overlay-for-stroke trick is no longer required since iOS 17:

Circle()
    .fill(.blue)
    .stroke(.white, lineWidth: 2)

ForEach + enumerated

Don't convert to an array first:

ForEach(Array(items.enumerated()), id: \.element.id) { ... }    // Bad
ForEach(items.enumerated(), id: \.element.id) { offset, item in ... }    // Good

Grammar agreement

For supported languages (English, French, German, Portuguese, Spanish, Italian), use automatic grammar agreement:

Text("^[\(people) person](inflect: true)")

Text concatenation

Never use + to concatenate Text:

// Bad and deprecated
Text("Hello").foregroundStyle(.red)
+
Text("World").foregroundStyle(.blue)

// Good — interpolation
let red = Text("Hello").foregroundStyle(.red)
let blue = Text("World").foregroundStyle(.blue)
Text("\(red)\(blue)")

ObservableObject

If you must use ObservableObject (e.g., for a Combine-based debouncer), add import Combine explicitly — SwiftUI no longer re-exports it.

Learn More

This guidance is adapted from the SwiftUI Pro agent skill by Paul Hudson (MIT-licensed).