(FastLd-JS) fastld-js

A fast, lightweight, and high-performance language detection library based on n-gram matching (2-, 3-, and 4-grams). Written in pure JavaScript with zero dependencies, works completely offline. Supports 130+ languages.

GitHub: https://github.com/zendtay-studio/fastld-js

⚡ Performance

This library is optimized for speed. Using an in-memory indexed search (PURE_MATCH_ARRAY), detection takes only fractions of a millisecond per text, making it ideal for real-time and batch processing where analytical performance is critical.

⚠️ Known Limitation

Short texts (e.g., one or two words) do not work reliably. The detection relies on statistical frequency of n-grams, so a medium to long text is required for accurate results.

📦 Installation

npm install fastld-js

🚀 API Usage

All functions are exposed from the main index.js file.

1. Detect main language (detect)

Returns the most probable language, or a limited number of top results.

const { detect } = require('fastld-js');

const text = "La familia salió de viaje hacia la playa el fin de semana pasado.";

// Get the most likely language
const result = detect(text);
console.log(result);
/*
Output:
{
  code: 'es',
  code2: 'spa',
  name: 'Spanish',
  accuracy: 0.8543,
  matches: 120,
  total: 140
}
*/

// Get top N results by passing a number
const top3 = detect(text, 3);
console.log(top3); // Array of the 3 most probable languages

2. Get full breakdown (detectAll)

Analyzes the text and returns a sorted array (highest to lowest accuracy) of all supported languages that had matches.

const { detectAll } = require('fastld-js');

const text = "The family went on a trip to the beach last weekend.";
const allLanguages = detectAll(text);

console.log(allLanguages[0]);
/*
Output:
{
  code: 'en',
  code2: 'eng',
  name: 'English',
  accuracy: 0.8912,
  matches: 135,
  total: 151
}
*/

3. Database information (getDatabaseInfo)

Returns technical details about the internally loaded data model.

const { getDatabaseInfo } = require('fastld-js');

const dbInfo = getDatabaseInfo();
console.log(dbInfo);

Current technical specifications:

• Type: PURE_MATCH_ARRAY
• Languages: 130
• Total n-grams: 254,497
• Config: 2, 3, 4-grams, top 9000 per language

📄 License

Apache 2.0 © ZendTay Studio