National Preventative Mechanism


    1.0.0-beta34 • Public • Published

    i18next Parser Build Status


    When translating an application, maintaining the translation catalog by hand is painful. This package parses your code and automates this process.

    Finally, if you want to make this process even less painful, I invite you to check Locize. They are a sponsor of this project. Actually, if you use this package and like it, supporting me on Patreon would mean a great deal!

    Become a Patreon


    • Choose your weapon: A CLI, a standalone parser or a stream transform
    • 5 built in lexers: Javascript, JSX, HTML, Handlebars, and TypeScript+tsx
    • Creates one catalog file per locale and per namespace
    • Backs up the old keys your code doesn't use anymore in namespace_old.json catalog
    • Restores keys from the _old file if the one in the translation file is empty
    • Supports i18next features:
      • Context: keys of the form key_context
      • Plural: keys of the form key_plural and key_plural_0
    • Tested on Node 6+

    DISCLAIMER: 1.0.0-beta

    1.x is currently in beta. You can follow the pre-releases here. It is a deep rewrite of this package that solves many issues, the main one being that it was slowly becoming unmaintainable. The migration contains all the breaking changes. Everything that follows is related to 1.x. If you rely on a 0.x.x version, you can still find the old documentation on its dedicated branch.



    You can use the CLI with the package installed locally but if you want to use it from anywhere, you better install it globally:

    yarn global add i18next-parser@next
    npm install -g i18next-parser@next
    i18next 'app/**/*.{js,hbs}' 'lib/**/*.{js,hbs}' [-oc]

    Multiple globbing patterns are supported to specify complex file selections. You can learn how to write globs here. Note that glob must be wrapped with single quotes when passed as arguments.

    IMPORTANT NOTE: If you pass the globs as CLI argument, they must be relative to where you run the command (aka relative to process.cwd()). If you pass the globs via the input option of the config file, they must be relative to the config file.

    • -c, --config : Path to the config file (default: i18next-parser.config.js).
    • -o, --output : Path to the output directory (default: locales/$LOCALE/$NAMESPACE.json).
    • -S, --silent: Disable logging to stdout.


    Save the package to your devDependencies:

    yarn add -D i18next-parser@next
    npm install --save-dev i18next-parser@next

    Gulp defines itself as the streaming build system. Put simply, it is like Grunt, but performant and elegant.

    const i18nextParser = require('i18next-parser').gulp;
    gulp.task('i18next', function() {
        .pipe(new i18nextParser({
          locales: ['en', 'de'],
          output: 'locales/$LOCALE/$NAMESPACE.json'

    IMPORTANT: output is required to know where to read the catalog from. You might think that gulp.dest() is enough though it does not inform the transform where to read the existing catalog from.


    Save the package to your devDependencies:

    yarn add -D i18next-parser@next
    npm install --save-dev i18next-parser@next

    Broccoli.js defines itself as a fast, reliable asset pipeline, supporting constant-time rebuilds and compact build definitions.

    const Funnel = require('broccoli-funnel')
    const i18nextParser = require('i18next-parser').broccoli;
    const appRoot = 'broccoli'
    let i18n = new Funnel(appRoot, {
      files: ['handlebars.hbs', 'javascript.js'],
      annotation: 'i18next-parser'
    i18n = new i18nextParser([i18n], {
      output: 'broccoli/locales/$LOCALE/$NAMESPACE.json'
    module.exports = i18n


    Using a config file gives you fine-grained control over how i18next-parser treats your files. Here's an example config showing all config options with their defaults.

    // i18next-parser.config.js
    module.exports = {
      contextSeparator: '_',
      // Key separator used in your translation keys
      createOldCatalogs: true,
      // Save the \_old files
      defaultNamespace: 'translation',
      // Default namespace used in your i18next config
      defaultValue: '',
      // Default value to give to empty keys
      indentation: 2,
      // Indentation of the catalog files
      keepRemoved: false,
      // Keep keys from the catalog that are no longer in code
      keySeparator: '.',
      // Key separator used in your translation keys
      // If you want to use plain english keys, separators such as `.` and `:` will conflict. You might want to set `keySeparator: false` and `namespaceSeparator: false`. That way, `t('Status: Loading...')` will not think that there are a namespace and three separator dots for instance.
      // see below for more details
      lexers: {
        hbs: ['HandlebarsLexer'],
        handlebars: ['HandlebarsLexer'],
        htm: ['HTMLLexer'],
        html: ['HTMLLexer'],
        js: ['JavascriptLexer'], // if you're writing jsx inside .js files, change this to JsxLexer
        jsx: ['JsxLexer'],
        mjs: ['JavascriptLexer'],
        ts: ['TypescriptLexer'],
        tsx: ['TypescriptLexer'],
        default: ['JavascriptLexer']
      lineEnding: 'auto',
      // Control the line ending. See options at
      locales: ['en', 'fr'],
      // An array of the locales in your applications
      namespaceSeparator: ':',
      // Namespace separator used in your translation keys
      // If you want to use plain english keys, separators such as `.` and `:` will conflict. You might want to set `keySeparator: false` and `namespaceSeparator: false`. That way, `t('Status: Loading...')` will not think that there are a namespace and three separator dots for instance.
      output: 'locales/$LOCALE/$NAMESPACE.json',
      // Supports $LOCALE and $NAMESPACE injection
      // Supports JSON (.json) and YAML (.yml) file formats
      // Where to write the locale files relative to process.cwd()
      input: undefined,
      // An array of globs that describe where to look for source files
      // relative to the location of the configuration file
      reactNamespace: false,
      // For react file, extract the defaultNamespace -
      // Ignored when parsing a `.jsx` file and namespace is extracted from that file.
      sort: false,
      // Whether or not to sort the catalog
      useKeysAsDefaultValue: false,
      // Whether to use the keys as the default value; ex. "Hello": "Hello", "World": "World"
      // The option `defaultValue` will not work if this is set to true
      verbose: false
      // Display info about the parsing including some stats


    The lexers option let you configure which Lexer to use for which extension. Here is the default:

    Note the presence of a default which will catch any extension that is not listed. There are 5 lexers available: HandlebarsLexer, HTMLLexer, JavascriptLexer, JsxLexer, and TypescriptLexer. Each has configurations of its own. If you need to change the defaults, you can do it like so:


    The Javascript lexer uses Acorn to walk through your code and extract references translation functions. If your code uses features not supported natively by Acorn, you can enable support through injectors and plugins configuration. Note that you must install these additional dependencies yourself through yarn or npm; they are not included in this package. This is an example configuration that adds all non-jsx plugins supported by acorn at the time of writing:

    const injectAcornStaticClassPropertyInitializer = require('acorn-static-class-property-initializer/inject');
    const injectAcornStage3 = require('acorn-stage3/inject');
    const injectAcornEs7 = require('acorn-es7');
    // ...
      js: [{
        lexer: 'JavascriptLexer'
        functions: ['t'], // Array of functions to match
        // acorn config (for more information on the acorn options, see here:
        acorn: {
          injectors: [
          plugins: {
            // The presence of these plugin options is important -
            // without them, the plugins will be available but not
            // enabled.
            staticClassPropertyInitializer: true,
            stage3: true,
            es7: true,
    // ...

    If you receive an error that looks like this:

    TypeError: baseVisitor[type] is not a function
    # rest of stack trace... 

    The problem is likely that you are missing a plugin that supports a feature that your code uses.

    The default configuration is below:

      // JavascriptLexer default config (js, mjs)
      js: [{
        lexer: 'JavascriptLexer'
        functions: ['t'], // Array of functions to match
        // acorn config (for more information on the acorn options, see here:
        acorn: {
          sourceType: 'module',
          ecmaVersion: 9, // forward compatibility
          // Allows additional acorn plugins via the exported injector functions
          injectors: [],
          plugins: {},


    The JSX lexer builds off of the Javascript lexer, and additionally requires the acorn-jsx plugin. To use it, add acorn-jsx to your dev dependencies:

    npm install -D acorn-jsx
    # or 
    yarn add -D acorn-jsx

    Default configuration:

      // JsxLexer default config (jsx)
      // JsxLexer can take all the options of the JavascriptLexer plus the following
      jsx: [{
        lexer: 'JsxLexer',
        attr: 'i18nKey', // Attribute for the keys
        // acorn config (for more information on the acorn options, see here:
        acorn: {
          sourceType: 'module',
          ecmaVersion: 9, // forward compatibility
          injectors: [],
          plugins: {},


    The Typescript lexer builds off of the JSX lexer, and additionally requires Typescript. To use it, add both typescript and acorn-jsx to your dev dependencies:

    npm install -D typescript acorn-jsx
    # or 
    yarn add -D typescript acorn-jsx

    If you need additional plugins, you can install them in the same way as described in the Javascript lexer configuration.

    Default configuration:

      // TypescriptLexer default config (ts/x)
      // TypescriptLexer can take all the options of the JsxLexer in addition to
      // optional tsOptions to pass as compilerOptions to TypeScript.
      ts: [{
        lexer: 'TypescriptLexer',
        attr: 'i18nKey', // Attribute for the keys
        // compiler options (
        // note that jsx MUST be set to Preserve, or your strings will not be extracted.
        tsOptions: {
          jsx: 'Preserve',
          target: 'esnext'


      // HandlebarsLexer default config (hbs, handlebars)
      handlebars: [{
        lexer: 'HandlebarsLexer',
        functions: ['t'] // Array of functions to match


      // HtmlLexer default config (htm, html)
      html: [{
        lexer: 'HtmlLexer',
        attr: 'data-i18n' // Attribute for the keys
        optionAttr: 'data-i18n-options' // Attribute for the options


    The transform emits a reading event for each file it parses:

    .pipe( i18next().on('reading', (file) => {}) )

    The transform emits a error:json event if the JSON.parse on json files fail:

    .pipe( i18next().on('error:json', (path, error) => {}) )

    The transform emits a warning:variable event if the file has a key that contains a variable:

    .pipe( i18next().on('warning:variable', (path, key) => {}) )


    Any contribution is welcome. Please read the guidelines first.

    Thanks a lot to all the previous contributors.

    If you use this package and like it, supporting me on Patreon is another great way to contribute!

    Become a Patreon

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