resources

name	resources
description	Manages localization and shared resources. Use when adding localized strings, working with String extensions, adding translations, or configuring the Resources module.

Skill: Resources

Guide for the Resources module: localization and shared resources.

When to use this skill

• Work with localized strings
• Add new translations
• Understand the localization system
• Add support for a new language

---

Module Overview

The Resources module provides app-specific resources used across features:

• Localization: Centralized strings with String.localized() extension
• Bundle: Manual Bundle.module accessor for resources

Location: Shared/Resources/

Note: Shared modules are app-specific (not reusable across apps), unlike Libraries which are generic and reusable.

Supported Languages

Language	Code	Status
English	en	Source language
Spanish	es	Fully translated

The app uses .xcstrings format (Apple's modern localization format for iOS 16+).

Structure:

Shared/Resources/
├── Package.swift
├── Sources/
│   ├── Extensions/
│   │   └── String+Localized.swift    # localized() extension
│   └── Resources/
│       └── Localizable.xcstrings
└── Tests/

---

Localization

All localized strings are centralized in the Resources module.

Location: Shared/Resources/Sources/Resources/Localizable.xcstrings

String Extension

The localized() extension converts string keys to localized values:

// Shared/Resources/Sources/Extensions/String+Localized.swift
public extension String {
    func localized() -> String {
        Bundle.module.localizedString(forKey: self, value: nil, table: nil)
    }

    func localized(_ arguments: CVarArg...) -> String {
        String(format: localized(), arguments: arguments)
    }
}

Why this pattern? It allows type-safe, reusable localization without repeating bundle references. Translations are managed manually in .xcstrings files.

---

Usage in Views

Each View defines a private LocalizedStrings enum that uses localized():

import {AppName}Resources

struct MyView: View {
    var body: some View {
        Text(LocalizedStrings.title)
    }
}

// MARK: - LocalizedStrings

private enum LocalizedStrings {
    static var title: String { "myView.title".localized() }
    static var subtitle: String { "myView.subtitle".localized() }
    static func itemCount(_ count: Int) -> String {
        "myView.itemCount %lld".localized(count)
    }
}

Adding New Strings

1. Add the key to Shared/Resources/Sources/Resources/Localizable.xcstrings
2. Provide translations for all supported languages (en, es)
3. Add the string to the View's private LocalizedStrings enum

String Key Naming Convention

Pattern	Example
{screen}.{element}	home.title
{screen}.{section}.{element}	characterList.empty.title
common.{element}	common.tryAgain

---

Bundle.module

SPM automatically generates Bundle.module for targets that declare resources in their Package.swift. No manual Bundle+Module.swift is needed.

Used by: String.localized() to access Localizable.xcstrings.

---

Project Configuration

The main app must declare supported languages in Project.swift via CFBundleLocalizations:

// Project.swift
let appInfoPlist: [String: Plist.Value] = [
    "CFBundleLocalizations": ["en", "es"],
    // ...
]

Important: iOS does not load localizations from embedded frameworks unless the main app declares supported languages in CFBundleLocalizations. Without this configuration, the app will always display the development language (English) regardless of device settings.

---

Adding a New Language

1. Open Localizable.xcstrings in Xcode
2. Click the "+" button to add a new language
3. Translate all strings to the new language
4. Update CFBundleLocalizations in Project.swift:

   "CFBundleLocalizations": ["en", "es", "NEW_LANG_CODE"],
   

5. Regenerate the project: ./Scripts/generate.sh

---

Checklist

Adding Localized Strings

• Add key to Localizable.xcstrings with all translations
• Add to View's private LocalizedStrings enum
• Use localized() or localized(_:) for interpolation

Adding a New Language

• Add language to Localizable.xcstrings in Xcode
• Translate all existing strings
• Add language code to CFBundleLocalizations in Project.swift
• Regenerate project with ./Scripts/generate.sh