How is data passed to child components within a hierarchy in SwiftUI?

In SwiftUI, data passing to child components is usually done through properties passed to the initializer of the child View. This can be a simple value or a binding if the child component needs to modify the data.

Example of passing a value:

struct ParentView: View {
    let title = "Hello, SwiftUI!"

    var body: some View {
        ChildView(text: title)
    }
}

struct ChildView: View {
    let text: String

    var body: some View {
        Text(text)
    }
}

If you want the child component to be able to modify the data, you use @Binding:

struct ParentView: View {
    @State private var isOn = false

    var body: some View {
        ToggleView(isOn: $isOn)
    }
}

struct ToggleView: View {
    @Binding var isOn: Bool

    var body: some View {
        Toggle("Enable", isOn: $isOn)
    }
}

Thus, data is passed down through parameters, and changes can be passed back via bindings.