# generaltranslation: General Translation Core SDK: requiresTranslation
URL: https://generaltranslation.com/en-GB/docs/core/class/methods/locales/requires-translation.mdx
---
title: requiresTranslation
description: API reference for the GT requiresTranslation method
---

## Overview

The `requiresTranslation` method determines whether translation is needed based on the source and target locales.
It checks whether the source content needs to be translated by comparing locale codes and considering the approved locale list.

***

## Reference

### Parameters

<TypeTable
  type={{
  "sourceLocale?": {
    type: 'string',
    optional: true,
    default: 'this.sourceLocale'
  },
  "targetLocale?": {
    type: 'string', 
    optional: true,
    default: 'this.targetLocale'
  },
  "approvedLocales?": {
    type: 'string[]',
    optional: true,
    default: 'this.locales'
  },
  "customMapping?": {
    type: 'CustomMapping',
    optional: true,
    default: 'this.customMapping'
  }
}}
/>

### Parameter descriptions

| Parameter         | Description                                                                                |
| ----------------- | ------------------------------------------------------------------------------------------ |
| `sourceLocale`    | The source locale code. If not provided, uses the instance&#39;s `sourceLocale`            |
| `targetLocale`    | The target locale code. If not provided, uses the instance&#39;s `targetLocale`            |
| `approvedLocales` | Array of approved target locales. If not provided, uses the instance&#39;s `locales` array |
| `customMapping`   | Optional custom mapping for locale resolution                                              |

### Returns

`boolean` - `true` if translation is required, `false` otherwise

### Throws

* `Error` - If no source locale is provided and the instance has no `sourceLocale` configured
* `Error` - If no target locale is provided and the instance has no `targetLocale` configured

***

## Examples

```typescript
const gt = new GT({
  sourceLocale: 'en-US',
  targetLocale: 'es-ES',
  locales: ['en-US', 'es-ES', 'fr-FR', 'de-DE']
});

// Different languages require translation
console.log(gt.requiresTranslation('en-US', 'es-ES')); // true
console.log(gt.requiresTranslation('en-US', 'fr-FR')); // true

// Same languages don't require translation
console.log(gt.requiresTranslation('en-US', 'en-US')); // false
console.log(gt.requiresTranslation('es-ES', 'es-ES')); // false

// Different dialects of same language don't require translation
console.log(gt.requiresTranslation('en-US', 'en-GB')); // false
console.log(gt.requiresTranslation('es-ES', 'es-MX')); // false

// Target not in approved locales
console.log(gt.requiresTranslation('en-US', 'it-IT')); // false (it-IT not in approved locales)
```

***


## Notes

* Considers locale language families, not just exact matches
* Respects approved locale lists
* Returns `false` when the target locale is not in the approved locales (if provided)

## Next steps

* Check locale relationships with [`isSameLanguage`](/docs/core/class/methods/locales/is-same-language)
* Determine the best locale with [`determineLocale`](/docs/core/class/methods/locales/determine-locale)
* Validate locales with [`isValidLocale`](/docs/core/class/methods/locales/is-valid-locale)