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Localization workflow for Browserify

How does this work?

This is a Browserify-based workflow for localizing client side applications. It is built for use cases where you can and want to ship one bundle per locale. Strings are defined by calling a pseudo-global function (i.e. __(string, args..)) in the default language in your code (similar to GNU gettext or similar). Strings are stored in .po files.


Install from npm:

npm install @offen/l10nify

This installs two things:

  • a Browserify transform for localizing strings at bundle time. It is references as @offen/l10nify
  • a extract-strings command that you can use to generate PO files from your JavaScript code.


Defining strings in client side code

In your code, use the __(string, args...) function (__ is the default, but you can use anything) to declare strings in your default language (which defaults to en but can be anything you want it to):

const HappyBirthdayComponent = (props) => {
  return (
    <h1>{__('Happy birthday, %s!', props.name)}</h1>

Extract strings from your code

Next, you can extract these strings from your code into .po files using the extract-strings command:

$(npm bin)/extract-strings **/*.js

This will extract the strings from all matching files and print a .po file to stdout. Use the standard gettext tools like msgmerge and msgcat to combine the output with existing .po files.

Refer to extract-strings --help for a full list of options

Why not just use xgettext

While xgettext works perfectly fine on ES5 code, it will choke on ES6+ syntax and also does not support parsing JSX, which l10nify supports.

Apply the transform at bundle time

Apply the transform to your Browserify setup passing the target locale. In development, you can omit this parameter to make the transform return the default locale, i.e. the strings you defined in code.

var browserify = require('browserify')

var b = browserify()
b.transform('@offen/l10nify', { locale: 'fr' })
b.bundle(function (err, src) {
  // consume bundle


The following options can be passed to the transform:


locale specifies the locale which you want to return when bundling. It defaults to en or process.env.LOCALE when set.


defaultLocale specifies the default locale that is used to define strings in code. It defaults to en or process.env.DEFAULT_LOCALE when set.


source specifies the directory in which the <LOCALE>.po files are stored. It defaults to ./locales or process.env.SOURCE when set.


global defines the global function identifier that is used for defining strings in code. It defaults to __ or process.env.GLOBAL when set.


Copyright 2020 Frederik Ring - l10nify is available under the MIT License

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