How to know which button is selected in SwiftUI?

I want to create 3 buttons. When I press on one button, I want that to be expand it with the x button. But instead of that, nothing happens. What am I doing wrong ? I will paste the code below.

This is the reutilizabile button I've created.

struct RCHChipView: View {
    var rchChip: RCHChip
    var action: () -> Void

    init(
        rchChip: RCHChip,
         action: @escaping () -> Void) {
        self.rchChip = rchChip
        self.action = action
    }

    var body: some View {
        HStack(spacing: 0) {
            Button {
                action()
            } label: {
                Text(rchChip.title)
            }
            if rchChip.isSelected {
                Button {
                    rchChip.isSelected = false
                } label: {
                        Image("NavigationCloseIcon")
                            .resizable()
                }
            }
        }
    }
}

struct RCHChip: Identifiable {
    var id: String
    var title: String
    @Binding var isSelected: Bool
    init(id: String = UUID().uuidString, title: String, isSelected: Binding<Bool> = .constant(false)) {
        self.id = id
        self.title = title
        self._isSelected = isSelected
    }
}

Here, I will show you how I'm trying to display the buttons.

 @State private var rchChip: [RCHChip] = [RCHChip(title: "Datum"), RCHChip(title: "Person")]
                        HStack {
                            ForEach(rchChip) { chip in
                                RCHChipView(rchChip: rchChip.first(where: {$0.id == chip.id}) ?? RCHChip(id: "", title: "", isSelected: .constant(false))) {
                                    chip.isSelected = true
                                }
                            }
                        }

How can I solve this issue ?

Your code is quite strange and I didn't really understand all of it but here is a solution that seems to work

First of all, you cannot use @Binding outside a View so I changed the struct to

struct RCHChip: Identifiable {
    var id: String
    var title: String
    var isSelected: Bool
    init(id: String = UUID().uuidString, title: String, isSelected: Bool = false) {
        self.id = id
        self.title = title
        self.isSelected = isSelected
    }
}

In the RCHChipView I found the definition of action strange since it didn't take any input nor returned anything. I changed it to the have the following signature

var action: (RCHChip) -> RCHChip

and to be able to modify a view property from outside of the view it needs to be a @Bindning so I changed rchChip to

@Binding var rchChip: RCHChip

the execution of the action property was then changed to

Button {
    self.rchChip = action(rchChip)
}

And for the calling view I used the following code

@State private var rchChips: [RCHChip] = [RCHChip(title: "Datum"), RCHChip(title: "Person")]

var body: some View {
    HStack {
        ForEach($rchChips) { chip in
            RCHChipView(rchChip: chip, action: { chip in
                var copy = chip
                copy.isSelected = true
                return copy
            })
        }
    }
}

I am sure this can be improved upon but it should be a step forward compared to your current solution and it does compile and run

I think this is to do with the behaviour of Binding variables.

Try:

struct RCHChipView: View {
    var rchChip: RCHChip
    var action: () -> Void

    init(
        rchChip: RCHChip,
         action: @escaping () -> Void) {
        self.rchChip = rchChip
        self.action = action
    }

    var body: some View {
        HStack(spacing: 0) {
            Button {
                action()
            } label: {
                Text(rchChip.title)
            }
            if rchChip.isSelected {
                Button {
                    rchChip.isSelected.wrappedValue = false
                } label: {
                        Image("NavigationCloseIcon")
                            .resizable()
                }
            }
        }
    }
}

The only difference being using the .wrappedValue for the Binding variable. Here's a slight change to the ForEach:

ForEach($rchChip) { $chip in
    RCHChipView(
        rchChip: chip,
        action: { $chip.wrappedValue.isSelected = true }
    )
}

$ is how you refer to Binding variables.