CODE EXAMPLE FOR SWIFT

detect binding valu change swiftui

struct TypewriterTextView: View {
    @Binding var textString:String
    @State private var typingInterval = 0.3
    @State private var typedString = ""

    var body: some View {
        Text(typedString).onChange(of: textString) {
            typedString = ""
            Timer.scheduledTimer(withTimeInterval: self.typingInterval, repeats: true, block: { timer in

                if self.typedString.length < self.textString.length {
                    self.typedString = self.typedString + self.textString[self.typedString.length]
                }
                else { timer.invalidate() }
            })
        }
    }
}