What approaches and principles should be considered when developing a design system for an app using SwiftUI?

When developing a design system for a SwiftUI application, it is important to consider the following principles:

• Component Consistency: create reusable components with the same style and behavior.
• Responsiveness: the design should look good on different devices and orientations.
• Theming: use system colors and fonts, support light and dark themes.
• Modularity: components should be independent and easily combinable.
• Documentation: describe the usage of components and their parameters.

In SwiftUI, it is convenient to use ViewModifier and custom components to standardize styles. For example:

struct PrimaryButtonStyle: ButtonStyle {
    func makeBody(configuration: Configuration) -> some View {
        configuration.label
            .padding()
            .background(Color.blue)
            .foregroundColor(.white)
            .cornerRadius(8)
            .opacity(configuration.isPressed ? 0.7 : 1.0)
    }
}

// Usage:
Button("Press me") {
    // action
}
.buttonStyle(PrimaryButtonStyle())

This approach helps maintain consistency and simplifies interface support.