# @johnhenry/langdetect-lite

> Dependency-free script and Latin-language detection (port of laya-mlx lang.py)

Latest version **0.1.1** (published 2026-09-23) · Apache-2.0 license · 0 weekly downloads

## Install

```sh
npm install @johnhenry/langdetect-lite
pnpm add @johnhenry/langdetect-lite
yarn add @johnhenry/langdetect-lite
bun add @johnhenry/langdetect-lite
```

## Health

**Score 65/100 (B)** — status: active.

Positive: esm support; no vulnerabilities; has provenance; recently updated; high maintenance score.

Warnings: low downloads; no types; pre 1.0.

## Facts

| | |
|---|---|
| Version | 0.1.1 |
| Published | 2026-09-23 |
| First published | 2026-09-23 |
| Weekly downloads | 0 |
| License | Apache-2.0 |
| TypeScript types | none |
| Module format | ESM |
| Node | >=24.0.0 |
| Dependencies | 1 |
| Unpacked size | 50.7 KB |
| Known vulnerabilities | 0 |
| Install scripts | no |
| Provenance | attested (GitHub Actions) |
| GitHub stars | 0 |
| Maintainers | johnhenry |
| Keywords | language-detection, langdetect, script-detection, i18n, nlp, zero-dependency |

## Links

- npm: https://www.npmjs.com/package/@johnhenry/langdetect-lite
- Repository: https://github.com/johnhenry/laya-js
- Homepage: https://github.com/johnhenry/laya-js/tree/main/packages/langdetect-lite
- Issues: https://github.com/johnhenry/laya-js/issues
- npm.io page: https://npm.io/package/@johnhenry/langdetect-lite

## Dependencies (1)

- [@johnhenry/pyjson](https://npm.io/package/@johnhenry/pyjson.md) ^0.1.2

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## Recent versions

- 0.1.1 (latest) — 2026-09-23
- 0.1.0 — 2026-09-23

## README

# @johnhenry/langdetect-lite

[![npm version](https://img.shields.io/npm/v/%40johnhenry%2Flangdetect-lite.svg)](https://www.npmjs.com/package/@johnhenry/langdetect-lite)

Script and Latin-language detection with no model and no data files: a faithful port of
laya-mlx `laya_mlx/lang.py` (from [Laya](https://github.com/NandhaKishorM/laya), Apache-2.0).
It answers one routing question: *can an English-only checkpoint read this text?*

## Install

```bash
npm install @johnhenry/langdetect-lite
bun add @johnhenry/langdetect-lite
deno add jsr:@johnhenry/langdetect-lite
```

Zero runtime dependencies beyond `@johnhenry/pyjson`; Node ≥ 24, Bun ≥ 1.2, Deno and browsers.

```js
import { analyse, isEnglish, detectScript, guessLatinLanguage } from "@johnhenry/langdetect-lite";

detectScript("客户被重复扣款要求退款");        // "han"
isEnglish("Please refund invoice 4411");         // true
isEnglish("Gătește-mi o rețetă de sarmale");     // false (Romanian diacritics)
guessLatinLanguage("Le client a ete facture deux fois et il demande un remboursement pour la facture"); // "fr"
analyse({ subject: "Refund", body: "Der Kunde wurde zweimal belastet und nicht erstattet" });
// { script: "latin", script_profile: { latin: 1 }, language: "de", is_english: false,
//   language_undecided: false, diacritic_rate: 0, non_latin_fraction: 0 }
```

## API

All functions accept a *state*: a string, or any JSON-like value whose string leaves
(object values and array items, up to depth 6) are joined with spaces. Keys are ignored.

| Export | Python (`laya_mlx.lang`) |
|---|---|
| `stateText(state, maxChars = 4000)` | `state_text` |
| `detectScript(text)` → `"latin" \| "han" \| ... \| "unknown"` | `detect_script` |
| `scriptProfile(text)` → `{ script: fraction }` | `script_profile` |
| `latinProfile(text)` → `{ language, english_hits, diacritic_rate, looks_non_english }` | `latin_profile` |
| `guessLatinLanguage(text)` → `"en" \| "fr" \| "de" \| "es" \| "pt" \| "it" \| "nl" \| "ro" \| null` | `guess_latin_language` |
| `analyse(state)` → `Analysis` | `analyse` |
| `isEnglish(state)` | `is_english` |
| `SCRIPT_RANGES`, `STOPWORDS`, `NON_EN_DIACRITICS`, `NON_EN_DIACRITIC_RATE` | module constants |

snake_case aliases (`state_text`, `detect_script`, ...) are exported too. Result objects
keep Python's snake_case keys so they compare equal to the Python output; every field of
the fixture table (`lang.json`, 35 states) matches exactly, floats included (rounding uses
`pyRound` from `@johnhenry/pyjson`, the only dependency).

Python semantics are reproduced where JavaScript differs: iteration and truncation by code
point (not UTF-16 unit), `str.isalpha()` as Unicode `\p{L}`, and `re` `[^\W\d_]+` as
`[\p{L}\p{Nl}\p{No}]+` (letters plus non-decimal numerics; combining marks split words,
as in Python).

## Limitations

- The Latin-language guess is a stopword/diacritic heuristic for 8 languages. Short input
  usually returns `null` (undecided) on purpose; Romanian without diacritics that contains an
  English function word reads as English. Pass an explicit language when you know it.
- Unicode tables come from the JavaScript engine, not from Python's `unicodedata`; the two
  can disagree on characters added in different Unicode versions.
- A state object's leaf order follows JavaScript key order (integer-like keys first), which
  only matters for the 4000-character truncation.

## Family

Part of **[laya-js](https://github.com/johnhenry/laya-js#readme)**, Laya typed decisions in JavaScript on MLX, WebGPU and CPU — see its [package map](https://github.com/johnhenry/laya-js#which-package-do-i-want) and [results](https://github.com/johnhenry/laya-js#results).

- [`@johnhenry/laya-router`](https://github.com/johnhenry/laya-js/tree/main/packages/laya-router) calls `analyse()` to choose between the English and multilingual checkpoints.
- Uses [`@johnhenry/pyjson`](https://github.com/johnhenry/laya-js/tree/main/packages/pyjson) for Python-identical number formatting in its reasons.

## License

Apache-2.0. Ports logic from [laya-mlx](https://github.com/mizorewww/laya-mlx) and [Laya](https://github.com/NandhaKishorM/laya) (both Apache-2.0); see [NOTICE](NOTICE).

---
_Source: https://npm.io/package/@johnhenry/langdetect-lite · Machine-readable twin of the npm.io package page. Health data is recomputed on every publish._