acc-lang-parser

1.0.4 verified Sat Apr 25 auth: no javascript maintenance

A simple parser for HTTP Accept-Language headers in Node.js. Version 1.0.4 (last released in 2016) extracts the first language or all language ranges from a header string. Returns objects with 'language' and 'locale' fields. Unlike more modern alternatives like 'accept-language-parser', this package has limited features, no TypeScript support, and is unmaintained. It was originally published under the npm name 'parse-acc-lang' (now deprecated) and later republished as 'acc-lang-parser'.

Common errors

error Error: Cannot find module 'parse-acc-lang' ↓

cause Using require('acc-lang-parser') instead of require('parse-acc-lang').

fix

Use require('parse-acc-lang') in your code, even though the npm package name is 'acc-lang-parser'.

error TypeError: parser.extractFirstLang is not a function ↓

cause Incorrect import path or using a different package version.

fix

Ensure you require('parse-acc-lang') and that the module exports the correct functions.

error Expected an object but got undefined ↓

cause Input header is null, undefined, or an empty string.

fix

Pass a valid Accept-Language header string. For null/undefined, manually handle or return a default.

Warnings

breaking Package name mismatch: npm package is 'acc-lang-parser' but require path uses 'parse-acc-lang'. ↓

fix Use require('parse-acc-lang') in code, not require('acc-lang-parser').

deprecated No TypeScript definitions available. ↓

fix Create your own .d.ts file or use a modern alternative with TypeScript support.

gotcha If extracted language tag has no locale (e.g., 'fr'), the locale field is an empty string ''. ↓

fix Check for empty locale string before use.

gotcha Quality values (q=) are ignored; the parser does not sort by weight. ↓

fix Use a more complete parser like 'accept-language-parser' if you need quality weighting.

Install

npm install acc-lang-parser

yarn add acc-lang-parser

pnpm add acc-lang-parser

Imports

parse-acc-lang
wrong
```
import parser from 'parse-acc-lang';
```
correct
```
const parser = require('parse-acc-lang');
```
This package is CommonJS-only, does not support ESM imports. The npm package name is 'acc-lang-parser' but the require path string is 'parse-acc-lang' (the old name).
extractFirstLang
```
const result = parser.extractFirstLang('de-DE');
```
Returns a single object with language and locale, or null if invalid input.

extractAllLangs

wrong

const results = parser.extractAllLangs('de-DE, en-GB', { strict: true });

correct

const results = parser.extractAllLangs('de-DE, en-GB');

Returns an array of objects. No options parameter is supported.

Quickstart

Parses an Accept-Language header to get the first language and all languages.

const parser = require('parse-acc-lang');
const header = 'de-DE, en-GB;q=0.9, fr;q=0.8';
const first = parser.extractFirstLang(header);
console.log(first); // { language: 'de', locale: 'DE' }
const all = parser.extractAllLangs(header);
console.log(all);
// [
//   { language: 'de', locale: 'DE' },
//   { language: 'en', locale: 'GB' },
//   { language: 'fr', locale: '' }
// ]