gettext.js is a lightweight (3k minified!) yet complete and accurate GNU gettext port for node and the browser. Manage your i18n translations the right way in your javascript projects.

Why another i18n javascript library?

gettext.js aim is to port the famous GNU gettext and ngettext functions to javascript node and browser applications. It should be standards respectful and lightweight (no dictionary loading management, no extra features).

The result is a < 200 lines javascript tiny lib yet implementing fully gettext() and ngettext() and having the lighter json translation files possible (embeding only translated forms, and not much headers).

There are plenty good i18n libraries out there, notably Jed and i18n-next, but either there are too complex and too heavy, or they do not embrace fully the gettext API and philosophy.

There is also gettext.js which is pretty good and heavily inspired this one, but not active since 2012 and without any tests.



Install the lib with the following command: npm install gettext.js --save

Require it in your project:

var i18n = require('gettext.js');


Download the latest archive or get it through bower: bower install gettext.js --save

<script src="/path/to/gettext.js" type="text/javascript"></script>
  var i18n = window.i18n(options);


Load your messages

You can load your messages these ways:

// i18n.setMessages(domain, locale, messages, plural_form);
i18n.setMessages('messages', 'fr', {
  "Welcome": "Bienvenue",
  "There is %1 apple": [
    "Il y a %1 pomme",
    "Il y a %1 pommes"
}, 'nplurals=2; plural=n>1;');
// i18n.loadJSON(jsonData /*, domain */);
var json = {
  "": {
    "locale": "fr",
    "plural-forms": "nplurals=2; plural=n>1;"
  "Welcome": "Bienvenue",
  "There is %1 apple": [
    "Il y a %1 pomme",
    "Il y a %1 pommes"
i18n.loadJSON(jsonData, 'messages');

See Required JSON format section below for more info.

Set the locale

You could do it from your dom

<html lang="fr">

or from javascript



Translate a string.

ngettext(msgid, msgid_plural, n)

Translate a pluralizable string

Variabilized strings

gettext('There are %1 in the %2, 'apples', 'bowl'); -> "There are apples in the bowl ngettext('One %2', '%1 %2', 10, 'bananas'); -> "10 bananas"`

It uses the public method i18n.strfmt("string", var1, var2, ...) you could reuse elsewhere in your project.

Required JSON format

You'll find in /bin a po2json.js converter, based on the excellent po2json project that will dump your .po files into the proper json format below:

    "": {
        "lang": "en",
        "plural_forms": "nplurals=2; plural=(n!=1);"
    "simple key": "It's tranlation",
    "another with %1 parameter": "It's %1 tranlsation",
    "a key with plural": [
        "a plural form",
        "another plural form",
        "could have up to 6 forms with some languages"
    "a context\u0004a contextualized key": "translation here"

Use bin/po2json.js input.po output.json or bin/po2json.js input.po output.json -p for pretty format.


You could use xgettext-php parser to parse your files. It provides helpful javascript and handlebars parsers.