Manipulating binding variables in SwiftUI - swift

Question

Suppose I have a string that's binding:
#Binding var string: String
But, I want to manipulate that string, and then pass it to a child view.
struct ViewOne: View {
#State var string: String = "Hello"
var body: some View {
ViewTwo(string: string + " World") // this is invalid, as ViewTwo requires Binding<String>
}
}
struct ViewTwo: View {
#Binding var string: String
var body: some View {
Text(string)
}
}
How should I go about manipulating that string, such that it will update the UI when the state changes? Let's assume that I want to re-use ViewTwo for different components, and so I would want to manipulate the string before it is passed to the view.
A computed variable doesn't work, as it isn't Binding
private var fixedString: String {
return string + " World"
}
And I don't want to create a binding variable, because the setter makes no sense in this context
private var fixedString: Binding<String> {
Binding<String> (
get: {
string + " World"
}, set: {
// this function doesn't make sense here - how would it update the original variable?
}
)
}
Am I just using #State and #Binding wrong?

Answer 1

Just remove the #Binding inside ViewTwo:
struct ViewTwo: View {
var string: String /// no need for the `#Binding`!
var body: some View {
Text(string)
}
}
SwiftUI will update ViewTwo even if you don't have the #Binding (it basically re-renders the entire body whenever a #State or #Published var gets changed).
You only need Bindings when you need to update/set the original #State or #Published property. In that case you'd add something like the var fixedString: Binding<String> in your question.