App Localization

App Localization

Manage iOS/macOS .strings files in Tuist-based projects.

Project Structure

<ModuleName>/
├── Resources/
│   ├── en.lproj/Localizable.strings       # Primary language (English)
│   ├── <locale>.lproj/Localizable.strings # Additional locales
│   └── ...
├── Derived/
│   └── Sources/
│       └── TuistStrings+<ModuleName>.swift  # Generated by Tuist
└── Sources/
    └── **/*.swift  # Uses <ModuleName>Strings.Section.key

After editing .strings files, run tuist generate to regenerate type-safe accessors.

Complete Localization Workflow

Step 1: Identify Hardcoded Strings

Find hardcoded strings in Swift files:

# Find Text("...") patterns with hardcoded strings
grep -rn 'Text("[A-Z]' <ModuleName>/Sources/
grep -rn 'title: "[A-Z]' <ModuleName>/Sources/
grep -rn 'label: "[A-Z]' <ModuleName>/Sources/
grep -rn 'placeholder: "[A-Z]' <ModuleName>/Sources/

Step 2: Add Translation Keys

Add keys to all language files:

en.lproj/Localizable.strings (primary):

/* Section description */
"section.key.name" = "English value";
"section.key.withParam" = "Value with %@";

Other locales (translate appropriately):

"section.key.name" = "<translated value>";
"section.key.withParam" = "<translated> %@";

Step 3: Generate Type-Safe Accessors

tuist generate

This creates Derived/Sources/TuistStrings+<ModuleName>.swift with accessors:

• <ModuleName>Strings.Section.keyName (static property)
• <ModuleName>Strings.Section.keyWithParam(value) (static function for %@ params)

See references/tuist-strings-patterns.md for detailed patterns.

Step 4: Update Swift Code

Replace hardcoded strings with generated accessors.

Pattern Mapping

Example Transformations

Before:

Text("Settings")
    .font(.headline)

TextField("Enter your name", text: $name)

Button("Submit") { ... }

Text("Hello, \(userName)!")

After:

Text(<Module>Strings.Section.settings)
    .font(.headline)

TextField(<Module>Strings.Field.namePlaceholder, text: $name)

Button(<Module>Strings.Action.submit) { ... }

Text(<Module>Strings.Greeting.hello(userName))

Handling Parameters and Plurals

String with parameter (key: "search.noResults" = "No results for \"%@\""):

// Before
Text("No results for \"\(searchText)\"")

// After
Text(<Module>Strings.Search.noResults(searchText))

Conditional plurals:

// Keys:
// "item.count" = "%d item"
// "item.countPlural" = "%d items"

// Swift:
let label = count == 1
    ? <Module>Strings.Item.count(count)
    : <Module>Strings.Item.countPlural(count)

Multiple parameters (key: "message.detail" = "%@ uploaded %d files"):

Text(<Module>Strings.Message.detail(userName, fileCount))

Step 5: Validate Changes

1. Build the project to catch missing keys
2. Run validation script to check consistency:

python scripts/validate_strings.py /path/to/<ModuleName>

AI-Powered Translation

When translating strings to non-English locales:

1. Read the English source string
2. Consider context from the key name (e.g., search.noResults = search UI)
3. Translate appropriately for the target locale:
   • zh-Hans: Simplified Chinese, formal but friendly
   • zh-Hant: Traditional Chinese
   • ja: Japanese, polite form (desu/masu style)
   • ko: Korean, polite form (hamnida/yo style)
   • de/fr/es/etc.: Appropriate regional conventions
4. Preserve all placeholders exactly (%@, %d, %ld, etc.)

Translation context by UI element:

• Labels: Keep concise
• Buttons: Action-oriented verbs
• Placeholders: Instructive tone
• Error messages: Helpful and clear
• Confirmations: Clear consequences

Validation Scripts

Validate .strings Files

python scripts/validate_strings.py /path/to/<ModuleName>

Checks for:

• Missing keys between languages
• Duplicate keys
• Placeholder mismatches (%@, %d, %ld)
• Untranslated strings (value = English)

Sync Missing Translations

Report missing keys:

python scripts/sync_translations.py /path/to/<ModuleName> --report

Add missing keys as placeholders:

python scripts/sync_translations.py /path/to/<ModuleName> --sync

Key Naming Convention

Pattern: "domain.context.element" → <Module>Strings.Domain.Context.element

Domain-Focused Naming (User Mental Model)

Keys should reflect what the user is doing, not technical UI components:

Good vs Bad Examples

Structure by Feature/Screen

Organize keys by the feature or screen where they appear:

/* Profile Section */
"profile.title" = "Profile";
"profile.name" = "Name";
"profile.save" = "Save Changes";
"profile.saveSuccess" = "Profile updated";

/* Beta Builds */
"betaBuild.title" = "Beta Builds";
"betaBuild.whatToTest" = "What to Test";
"betaBuild.submitForReview" = "Submit for Review";
"betaBuild.expireConfirm" = "Expire this build?";

/* Tester Groups */
"testerGroup.create" = "Create Group";
"testerGroup.addTester" = "Add Tester";
"testerGroup.empty" = "No testers yet";

This mirrors how users think: "I'm in Beta Builds, submitting for review" → betaBuild.submitForReview

.strings File Format

/* Comment describing the section */
"key.name" = "Value";
"key.with.parameter" = "Hello, %@!";
"key.with.number" = "%d items";
"key.with.multiple" = "%1$@ has %2$d items";

Rules:

• Keys must be unique within a file
• Values are UTF-8 encoded
• Escape quotes with backslash: \"
• Line ends with semicolon
• Use positional parameters (%1$@, %2$d) when order differs between languages