Turkish Suffix Library

A TypeScript library for handling Turkish language suffixes with proper vowel harmony and consonant softening rules.

Features

• ✅ Full support for Turkish vowel harmony (2-way and 4-way)
• ✅ Automatic consonant softening (yumuşama)
• ✅ Proper noun handling with apostrophes
• ✅ Foreign word support
• ✅ Abbreviation handling
• ✅ TypeScript support with full type safety
• ✅ Zero dependencies
• ✅ Comprehensive test coverage

Installation

npm install turkish-suffixes

or with Yarn:

yarn add turkish-suffixes

or with Bun:

bun add turkish-suffixes

Usage

import { withTurkishSuffix, TurkishCase } from 'turkish-suffixes';

// Plural
withTurkishSuffix('ev', TurkishCase.PLURAL); // 'evler'
withTurkishSuffix('araba', TurkishCase.PLURAL); // 'arabalar'

// Possessive
withTurkishSuffix('ev', TurkishCase.POSSESSIVE); // 'evin'
withTurkishSuffix('araba', TurkishCase.POSSESSIVE); // 'arabanın'

// Dative (to/for)
withTurkishSuffix('ev', TurkishCase.DATIVE); // 'eve'
withTurkishSuffix('okul', TurkishCase.DATIVE); // 'okula'

// Accusative (direct object)
withTurkishSuffix('ev', TurkishCase.ACCUSATIVE); // 'evi'
withTurkishSuffix('araba', TurkishCase.ACCUSATIVE); // 'arabayı'

// Locative (at/in/on)
withTurkishSuffix('ev', TurkishCase.LOCATIVE); // 'evde'
withTurkishSuffix('masa', TurkishCase.LOCATIVE); // 'masada'

// Ablative (from)
withTurkishSuffix('ev', TurkishCase.ABLATIVE); // 'evden'
withTurkishSuffix('okul', TurkishCase.ABLATIVE); // 'okuldan'

API Reference

withTurkishSuffix(text: string, suffix: TurkishCase): string

Applies a Turkish suffix to the given text with proper vowel harmony.

Parameters

• text: The word to apply the suffix to
• suffix: The type of suffix to apply (from TurkishCase enum)

TurkishCase Enum

enum TurkishCase {
    PLURAL = 'PLURAL', // -lar/-ler
    POSSESSIVE = 'POSSESSIVE', // -(n)ın/-(n)in/-(n)un/-(n)ün
    DATIVE = 'DATIVE', // -(y)a/-(y)e
    ACCUSATIVE = 'ACCUSATIVE', // -(y)ı/-(y)i/-(y)u/-(y)ü
    LOCATIVE = 'LOCATIVE', // -da/-de/-ta/-te
    ABLATIVE = 'ABLATIVE', // -dan/-den/-tan/-ten
    KI = 'ki' // -ki (unchanging)
}

Special Features

Proper Nouns

Proper nouns are automatically detected and handled with apostrophes:

withTurkishSuffix('Ali', TurkishCase.DATIVE); // "Ali'ye"
withTurkishSuffix('İstanbul', TurkishCase.LOCATIVE); // "İstanbul'da"
withTurkishSuffix('Ankara', TurkishCase.ABLATIVE); // "Ankara'dan"

Foreign Words

Mark foreign words with |y flag to prevent consonant softening:

withTurkishSuffix('computer|y', TurkishCase.POSSESSIVE); // "computer'ın"
withTurkishSuffix('laptop|y', TurkishCase.ACCUSATIVE); // "laptop'u"

Consonant Softening

The library automatically applies consonant softening rules:

withTurkishSuffix('kitap', TurkishCase.POSSESSIVE); // "kitabın" (p → b)
withTurkishSuffix('ağaç', TurkishCase.DATIVE); // "ağaca" (ç → c)
withTurkishSuffix('renk', TurkishCase.POSSESSIVE); // "rengin" (k → g)

Numbers and Abbreviations

withTurkishSuffix('2024', TurkishCase.LOCATIVE); // "2024'te"
withTurkishSuffix('TV', TurkishCase.DATIVE); // "TV'ye"
withTurkishSuffix('GPS', TurkishCase.ABLATIVE); // "GPS'den"

Vowel Harmony Rules

The library automatically applies Turkish vowel harmony rules:

2-Way Harmony (a/e)

• Back vowels (a, ı, o, u) → -a
• Front vowels (e, i, ö, ü) → -e

4-Way Harmony (ı/i/u/ü)

• Back unrounded (a, ı) → -ı
• Back rounded (o, u) → -u
• Front unrounded (e, i) → -i
• Front rounded (ö, ü) → -ü

Examples

Complete Example

import { withTurkishSuffix, TurkishCase } from 'turkish-suffixes';

const word = 'ev';

console.log(`${word}'in halleri:`);
console.log(`Çoğul: ${withTurkishSuffix(word, TurkishCase.PLURAL)}`); // evler
console.log(`İyelik: ${withTurkishSuffix(word, TurkishCase.POSSESSIVE)}`); // evin
console.log(`Yönelme: ${withTurkishSuffix(word, TurkishCase.DATIVE)}`); // eve
console.log(`Belirtme: ${withTurkishSuffix(word, TurkishCase.ACCUSATIVE)}`); // evi
console.log(`Bulunma: ${withTurkishSuffix(word, TurkishCase.LOCATIVE)}`); // evde
console.log(`Ayrılma: ${withTurkishSuffix(word, TurkishCase.ABLATIVE)}`); // evden

Real-world Usage

// Building sentences
const city = 'İstanbul';
const person = 'Ahmet';

console.log(`${withTurkishSuffix(person, TurkishCase.POSSESSIVE)} arabası`); // Ahmet'in arabası
console.log(`${withTurkishSuffix(city, TurkishCase.LOCATIVE)} yaşıyor`); // İstanbul'da yaşıyor
console.log(`${withTurkishSuffix(city, TurkishCase.ABLATIVE)} geliyor`); // İstanbul'dan geliyor

Development

Building

bun run build

Testing

bun test

Running Examples

bun run examples/usage.ts

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

1. Fork the repository
2. Create your feature branch (git checkout -b feature/amazing-feature)
3. Commit your changes (git commit -m 'Add some amazing feature')
4. Push to the branch (git push origin feature/amazing-feature)
5. Open a Pull Request

License

This project is licensed under the MIT License - see the LICENSE file for details.

Author

Semih Ayhan - @smhayhan

Acknowledgments

• Thanks to all contributors who have helped improve this library
• Inspired by the beauty and complexity of the Turkish language