cld-universal

Everyone has the right to resist occupation.

This is a fork of dachev/node-cld. The original project has had no maintainer activity in over a year, and has outdated dependencies causing 3 high severity security issues.

In addition to updating outdated dependencies, this fork adds a WASM fallback backend (native addon first, WASM if it's unavailable - see below), enabling use in environments without a C++ toolchain, including in the browser.

Maintenance expectations: this fork will receive best-effort security patches, but is unlikely to see further changes to the underlying CLD2 C++ core. If upstream development resumes and merges the WASM backend, this fork will be archived in favor of the original package.

Language detection for Javascript. Based on the CLD2 (Compact Language Detector) library from Google.

Highly optimized for space and speed. Runs about 10x faster than other libraries. Detects over 160 languages. Full test coverage. Runs on Linux, OS X, and Windows, and in the browser via a WASM fallback when the native addon is unavailable.

Installation

$ npm install cld-universal

If a native build isn't possible at install time (missing toolchain, browser bundling, etc.), the package falls back to a bundled WASM build automatically -- no extra configuration needed.

Linux users aiming to avoid falling back to WASM: make sure you have g++ >= 4.8.

Examples

Simple (ESM)

import cld from 'cld-universal';
const { detect } = cld;

// As a promise
const result = await detect('This is a language recognition example');
console.log(result);

Node's CommonJS/ESM interop doesn't reliably expose this package's named exports (detect, LANGUAGES, etc.) as ESM named imports: import { detect } from 'cld-universal' will throw a SyntaxError. Import the default export and destructure instead, as above.

Simple (CommonJS)

const cld = require('cld-universal');

// As a promise
cld.detect('This is a language recognition example').then((result) => {
  console.log(result);
});

// In an async function
async function testCld() {
  const result = await cld.detect('This is a language recognition example');
  console.log(result);
}

Advanced

import cld from 'cld-universal';
const { detect } = cld;

const text    = 'Това е пример за разпознаване на Български език';
const options = {
  isHTML       : false,
  languageHint : 'BULGARIAN',
  encodingHint : 'ISO_8859_5',
  tldHint      : 'bg',
  httpHint     : 'bg'
};

const result = await detect(text, options);
console.log(result);

Legacy callback style

detect() also accepts the node callback pattern. If options are provided, the third parameter is the callback.

const cld = require('cld-universal');

cld.detect('This is a language recognition example', (err, result) => {
  console.log(result);
});

Browser / bundlers

Bundlers (webpack, esbuild, Vite, etc.) resolve cld-universal to a WASM-only, browser-specific entry point via the package's "browser" export condition. That entry point is real ESM, so named imports work there:

import { detect, LANGUAGES } from 'cld-universal';

const result = await detect('This is a language recognition example');
console.log(result);

If your bundler serves the WASM binary from a non-default path (a CDN, a renamed/hashed asset, etc.), call setWasmModuleOptions({ locateFile }) before the first detect() call to override where cld.web.wasm is fetched from:

import { detect, setWasmModuleOptions } from 'cld-universal';

setWasmModuleOptions({
  locateFile: (path) => `/assets/${path}`,
});

const result = await detect('This is a language recognition example');

Result shape

detect() resolves to (or, in callback form, passes as the second argument) an object of the following shape:

Field	Type	Description
reliable	boolean	Whether CLD2 considers the detection reliable
textBytes	number	Number of bytes of text CLD2 actually looked at
languages	Array<{ name, code, percent, score }>	Detected languages, most likely first. percent is 0-100, score is CLD2's internal confidence score
chunks	Array<{ name, code, offset, bytes }>	Per-chunk breakdown showing which language was detected at which byte range of the input

TypeScript types for this shape (and for Options, below) ship with the package via index.d.ts — no @types package needed.

Options

Option	Type	Description
isHTML	boolean	Set to true if the string contains HTML tags
languageHint	string	A LANGUAGES key or value, passed as a hint
encodingHint	string	An ENCODINGS value, passed as a hint
tldHint	string	Top level domain, passed as a hint
httpHint	string	An HTTP Content-Encoding value, passed as a hint
bestEffort	boolean	Set to true to get a best-effort answer instead of UNKNOWN_LANGUAGE. Useful for short text if the caller prefers an approximate answer over none

Exported constants

Alongside detect, the package exports:

• LANGUAGES: an object mapping every language name CLD2 recognizes to its language code (e.g. { ENGLISH: 'en', ... }). Use its keys/values as languageHint.
• DETECTED_LANGUAGES: an array of the language names detect() can actually return in result.languages.
• ENCODINGS: an array of the encoding names usable as encodingHint.

Backends

This fork tries the native N-API addon first (built during npm install) and, if that's unavailable (build failed, no C++ toolchain, running in a bundler/browser) transparently falls back to a bundled WASM build of the same CLD2 sources. Both backends are tested against each other for output parity (see test/runner-wasm.js); there's no behavior difference to code using this package, and no configuration needed to opt into the fallback.

Warning

Once the module has been installed, the underlying C sources will remain in the deps/cld folder and continue to occupy considerable space. This is because they will be required if you ever need to run npm rebuild. If you are under severe constraints you can delete this folder and reclam >100M

Copyright

Copyright 2011-2015, Blagovest Dachev.

This fork Copyright 2026, Figulus Project.

License

Apache 2