Streamline your localized strings

Declaring a localizable string

• Use SwiftUI’s LocalizedStringKey initializers, e.g. Text("Hello world")

• via variables, e.g. button.title = NSLocalizedString("Order", comment: "…")

• new Swifty way: button.title = String(localized: "Order")

Example:

let count = 3

// SwiftUI
Button("Order \(count) Tickets") { … }

// Swift
button.title = String(localized: "Order \(count) Tickets")
// This was previously obtained via .localizedStringWithFormat()

• Do not use String(format: "Order %d Tickets", count), it’s not intended for localization.

Comment recommendations

Tips for a good localized string comment:

• declared the interface element (e.g. button)

• define the context

• explain each variable

Examples:

Text("Order", comment: "Button: confirms concert tickets booking")
Text("\(ticketCount) Ordered", comment: "Order summary: total number of tickets ordered")

Tables

• localized strings can be further organized in tables

• by default all strings are put in a table named Localizable, which means all strings are stored in a Localizable.strings and Localizable.stringsdict file

Which means that the following example will search for the localization in fr.lproj/UserProfile.strings for the French translation (for example)

Text(
  "\(ticketCount) Ordered",
  tableName: "UserProfile",
  comment: "Profile subtitle: total number of tickets ordered"
)

Bundle

• This parameter lets you load strings across targets

• .main by default

• if your app extension wants to use:

  • the same localizations as your app, there’s nothing else to do

  • its own localizations, it needs to set .module as the bundle parameter value

• if the localization is vended by a framework you’d use:

/// In the framework

public enum OrderStatus {
  case pending, processing, complete, canceled, invalid(Error)

  var displayName: String {
    switch self {
      case .complete: return String(
        localized: "Complete",
        bundle: Bundle(for: AnyClassInTicketKit.self),
        comment: "Standalone ticket status: order finalized"
      )
      ...
          
/// In the app:

Text(OrderStatus.complete.displayName)