Modern, standards-based RTL (Right-to-Left) language detection for JavaScript/TypeScript. Detects if a locale is RTL, gets text direction, and lists all Unicode/ISO RTL languages.
- Detect if a locale or language code is right-to-left (RTL)
- Get the text direction (
'rtl'or'ltr') for any locale - List all supported RTL language codes (Unicode/ISO-compliant)
- Fully immutable, type-safe, and fast
- Works in Node.js, browsers, and TypeScript projects
# npm
npm install @andreasnicolaou/rtl-detect
# yarn
yarn add @andreasnicolaou/rtl-detect
# pnpm
pnpm add @andreasnicolaou/rtl-detectFor direct browser usage without a build step:
<!-- unpkg CDN (latest version, unminified) -->
<script src="https://unpkg.com/@andreasnicolaou/rtl-detect/dist/index.umd.js"></script>
<!-- unpkg CDN (latest version, minified) -->
<script src="https://unpkg.com/@andreasnicolaou/rtl-detect/dist/index.umd.min.js"></script>
<!-- jsDelivr CDN (unminified) -->
<script src="https://cdn.jsdelivr.net/npm/@andreasnicolaou/rtl-detect/dist/index.umd.js"></script>
<!-- jsDelivr CDN (minified) -->
<script src="https://cdn.jsdelivr.net/npm/@andreasnicolaou/rtl-detect/dist/index.umd.min.js"></script>Note: The library will be available as
rtlLanguageDetectoron the global scope when loaded via CDN in the browser.
import {
isRtlLanguage,
getTextDirection,
getRtlLanguageCodes,
parseLocale,
RtlLanguageDetector,
} from '@andreasnicolaou/rtl-detect';
isRtlLanguage('ar'); // true
getTextDirection('fa-IR'); // 'rtl'
const rtlCodes = getRtlLanguageCodes();
const parsed = parseLocale('ar-EG');
RtlLanguageDetector.isRtlLanguage('he'); // trueconst {
isRtlLanguage,
getTextDirection,
getRtlLanguageCodes,
parseLocale,
RtlLanguageDetector,
} = require('@andreasnicolaou/rtl-detect');
isRtlLanguage('ar'); // true
getTextDirection('fa-IR'); // 'rtl'
const rtlCodes = getRtlLanguageCodes();
const parsed = parseLocale('ar-EG');
RtlLanguageDetector.isRtlLanguage('he'); // true<script src="https://unpkg.com/@andreasnicolaou/rtl-detect/dist/index.umd.min.js"></script>
<script>
const { isRtlLanguage, getTextDirection, getRtlLanguageCodes, parseLocale } = rtlLanguageDetector;
isRtlLanguage('ar'); // true
getTextDirection('fa-IR'); // 'rtl'
const rtlCodes = getRtlLanguageCodes();
const parsed = parseLocale('ar-EG');
rtlLanguageDetector.isRtlLanguage('he'); // true
</script>| Function/Export | Signature | Description |
|---|---|---|
| isRtlLanguage | (locale: string): boolean |
Returns true if the locale or language code is right-to-left. |
| getTextDirection | (locale: string): 'rtl' | 'ltr' |
Returns the text direction for the given locale. |
| getRtlLanguageCodes | (): readonly string[] |
Returns a frozen array of all supported RTL language codes. |
| parseLocale | (locale: string): ParsedLocaleInfo | undefined |
Parses a locale string into its language and country code components. Automatically strips encoding/variant suffixes (e.g., .UTF-8, @calendar=gregorian). |
| RtlLanguageDetector | class |
Static class with all the above as static methods. |
| Type | Definition | Description |
|---|---|---|
TextDirection |
'rtl' | 'ltr' |
Text direction, either right-to-left or left-to-right |
ParsedLocaleInfo |
{ language: string; countryCode?: string } |
Parsed locale object with language and optional country code |
This library uses an immutable list of RTL language codes (Unicode/ISO-compliant) to determine text direction for any locale or language code. It works in Node.js, browsers, and TypeScript projects, and is fully type-safe.
MIT
Contributions are welcome! Please open issues or pull requests for improvements or new features.