Validate Translation Keys Passed to t() (valid-translation-key)

This rule checks that the string key passed to the t() function matches a valid key defined in the TranslationKeys type. It ensures that all translations are statically verified and no invalid keys are used at runtime.

🧩 Rule Type

• Type: problem
• Category: Best Practices
• Fixable: No
• Recommended: No

📚 Why Validate Translation Keys?

• Prevents typos in translation keys.
• Avoids runtime translation errors or missing texts.
• Enables static checking of localization usage.
• Ensures consistency with your i18n type definitions.

✅ Correct Usage

// src/constants/localization/translation-keys.d.ts
export type TranslationKeys = {
  greetings: {
    hi: string;
    welcome: string;
  };
};

// any place in the code
t('greetings.hi');
t('greetings.welcome');

❌ Incorrect Usage

// Key does not exist in TranslationKeys
t('greetings.hello');
// Error: The translation key "greetings.hello" is not defined in TranslationKeys. Did you mean: "greetings.hi", "greetings.welcome"?

If a key is invalid, the rule will suggest possible alternatives using a string similarity algorithm (Levenshtein distance). Only suggestions with close matches are shown, and dynamic keys are ignored.

📂 Ignored Files

This rule applies to all files, but it only checks t() calls with a string literal as the first argument.

• t('greetings.' + dynamic)
• Any dynamic or non-literal key usage

🔍 When To Enable

Enable this rule when:

• You have a static TranslationKeys type in your project.
• You want to catch invalid translation keys during development.
• You want to enforce type-safe internationalization usage.

⚙️ Options

This rule does not take any configuration options.