swiftui-behind-the-scene-lifetime.swift

struct MarshallSpeaker: View {
    var maximumVolume: Int = 100
    @State var volume: Int = 50

    var body: some View {
        // UI code
    }

    public func updateVolume(volume: Int) {
        self.volume = volume < maximumVolume ? volume : maximumVolume
    }
}

let MarshallSpeakerBefore = MarshallSpeaker(volume: 50)
MarshallSpeakerBefore.updateVolume(volume: 80)

// Above statement generates a view with the new value
let MarshallSpeakerAfter = MarshallSpeaker(volume: 80)