In the article about the plurals to a localization (and any other documentation on this) give one var in the string eg

Text("\(project.projectItems.count) items")

then in stringdict file

<dict>
    <key>%lld items</key>
    <dict>
        <key>NSStringLocalizedFormatKey</key>
        <string>%#@VARIABLE@</string>
        <key>VARIABLE</key>
        <dict>
            <key>NSStringFormatSpecTypeKey</key>
            <string>NSStringPluralRuleType</string>
            <key>NSStringFormatValueTypeKey</key>
            <string>lld</string>
            <key>zero</key>
            <string>Empty</string>
            <key>one</key>
            <string>1 item</string>
            <key>other</key>
            <string>%lld items</string>
        </dict>
    </dict>
</dict>

however what do you do if you have two variables in the string eg

Text("Completed \(completed) of \(project.projectItems.count) items")

and stringdict

<dict>
    <key>Completed %lld of %lld items</key>
    <dict>
        <key>NSStringLocalizedFormatKey</key>
        <string>%#@VARIABLE@</string>
        <key>VARIABLE</key>
        <dict>
            <key>NSStringFormatSpecTypeKey</key>
            <string>NSStringPluralRuleType</string>
            <key>NSStringFormatValueTypeKey</key>
            <string>lld</string>
            <key>zero</key>
            <string>Empty</string>
            <key>one</key>
            <string>Completed %lld of 1 item</string>
            <key>other</key>
            <string>Completed %lld of %lld items</string>
        </dict>
    </dict>
</dict>

because this do not work properly. Can any help me to understand what to do?

You need to:

1. rename VARIABLE to something more useful
2. add more variable names for every thing you want to replace in the string
3. add a new key and dict for each new variable in your string

Here's an article showing what I mean: Step-by-step guide for localizing plurals in iOS

PS. Sorry I didn't include any code to illustrate. I'm typing this on my phone.

Ok, in the fresh light of day and on a Mac instead of a phone...

1. change your Text to this: Text("Completed \(completed) of \(project.projectItems.count)")
2. put this in your Localizable.stringsdict file:

<dict>
    <key>Completed %lld of %lld</key>
    <dict>
        <key>NSStringLocalizedFormatKey</key>
        <string>Completed %d of %#@projectItemsCount@</string>
        <key>projectItemsCount</key>
        <dict>
            <key>NSStringFormatSpecTypeKey</key>
            <string>NSStringPluralRuleType</string>
            <key>NSStringFormatValueTypeKey</key>
            <string>d</string>
            <key>one</key>
            <string>%d item</string>
            <key>other</key>
            <string>%d items</string>
        </dict>
    </dict>
</dict>

Cheers @roosterboy, I am getting tthe hang of it and got it to work, however I have something like this

struct ContentView: View {
    var number = 1
    var total = 1

    var open = true
    @State var message = ""

    var body: some View {
        VStack {
            Text(message)
        }
        .onAppear {
            if open {
                message = "Completed \(number) of \(total) items"
            } else {
                message = "Closed"
            }
        }
    }
}

and put this in the Localizable.stringsdict

<dict>
    <key>Completed %lld of %lld items</key>
    <dict>
        <key>NSStringLocalizedFormatKey</key>
        <string>Completed %lld of %#@total@</string>
        <key>total</key>
        <dict>
            <key>NSStringFormatSpecTypeKey</key>
            <string>NSStringPluralRuleType</string>
            <key>NSStringFormatValueTypeKey</key>
            <string>d</string>
            <key>zero</key>
            <string>Empty</string>
            <key>one</key>
            <string>%d item</string>
            <key>other</key>
            <string>%d items</string>
        </dict>
    </dict>
</dict>

I think because put Text(message) the stringdict do not work but if Text("Completed \(number) of \(total) items") works.

Thank you for your help.

PS. Did do a workaround that would let me add more change of a langange requires

if open {
  switch total {
  case 0:
      message = "Empty"
  case 1:
      message = "Completed \(number) of \(total) item"
  default:
      message = "Completed \(number) of \(total) items"
    }
} else {
  message = "Closed"
}