gulp-l10n

A gulp plugin that wraps s18n and provides simple tooling for localizing html. Perfect for static generated sites and applications.

By default, this plugin generates localized html files and outputs them to a subdirectory for each locale, a popular pattern for localizing web content. For example: when example.com/about is localized with the de locale, it is placed at example.com/de/about.

Usage

var gulp = require('gulp');
var l10n = require('gulp-l10n');
 
// Prior to localization, pipe your locales to the setLocales method
 
gulp.task('load-locales', function () {
  return gulp.src('locales/*.json')
    .pipe(l10n.setLocales());
});
 
// Files piped to the plugin are localized and cloned to a separate subdirectory
// for each locale. e.g.: 'index.html' > 'de/index.html'
 
gulp.task('localize', ['load-locales'], function () {
  return gulp.src('src/**/*.html')
    .pipe(l10n())
    .pipe(gulp.dest('dist'))
});
 
gulp.task('default', ['localize']);

Extracting Locales for Translation

The Extract method accepts an s18n extract options object. See s18n's extract options for full documentation and defaults.

var gulp = require('gulp');
var l10n = require('gulp-l10n');
 
var opts = {
  elements: ['title', 'p', 'h1'],
  attributes: ['alt', 'title'],
  directives: 'translate=yes',
  attributeSetter: 'translate-attrs'
};
 
gulp.task('extract-locales', function () {
  return gulp.src('src/**/*.html')
    .pipe(l10n.extract(opts))
    .pipe(gulp.dest('locales'));
});

Continuous Localization

To automatically extract new strings for translation, simply add your locale extraction task to your build process.

var gulp = require('gulp');
var l10n = require('gulp-l10n');
 
gulp.task('extract-locales', function () {
  return gulp.src('app/**/*.html')
    .pipe(l10n.extract())
    .pipe(gulp.dest('locales'));
});
 
gulp.task('load-locales', ['extract-locales'], function () {
  return gulp.src('locales/*.json')
    .pipe(l10n.setLocales());
});
 
gulp.task('localize', ['load-locales'], function () {
  return gulp.src('app/**/*.html')
    .pipe(l10n())
    .pipe(gulp.dest('dist'));
});
 
gulp.task('prepare', ['extract-locales']);
gulp.task('default', ['localize']);

Enforcing Localization

The enforce option of the setLocales method provides a way to warn or error when strings are not translated. With options.enforce set to warn, when any locale is missing a string from the native locale, setLocales will log the problem. With options.enforce set to strict, an error will be thrown.

...
 
gulp.task('load-locales', ['extract-locales'], function () {
  return gulp.src('locales/*.json')
    .pipe(l10n.setLocales({
      native: 'en',
      enforce: 'warn'
    }));
});
 
...

Example:

locales/en.json:

  {
    "37b51d19": "bar",
    "acbd18db": "foo"
  }

locales/de.json:

  {
    "37b51d19": "bår"
  }

Will warn:

WARN: locale `de` is missing: `acbd18db`, native string: `foo`

Testing Localization

To simulate translation (for testing purposes), you can use the s18n CLI's $ s18n map. See s18n Testing Localization for more information.

Rewriting hrefs

The hrefRewrite option accepts a function which transforms the contents of all a element href attributes in each locale. This is ideal for completely static sites, where little or no server logic is being employed to serve appropriate locales to visitors (eg: GitHub Pages). This rewriting allows users to navigate the static site within their chosen locale.

gulp.task('localize', ['load-locales'], function () {
  return gulp.src('app/**/*.html')
    .pipe(l10n({
      hrefRewrite: function(href, locale){
        if(href.charAt(0) === '/'){
          return '/' + locale + href;
        }
        else {
          return href;
        }
      }
    }))
    .pipe(gulp.dest('dist'));
});

Rewriting Other URLs and Attributes

The hrefRewrite option is deliberately limited in scope to a element hrefs. To localize other URLs, like image srcs, link hrefs, and other html attributes, it's recommended that s18n Attribute Setters and Cancelers be used. This ensures all localization information is available in locale files, rather than relying upon project configuration.

Multiple Projects

When localizing multiple projects with the same instance of gulp-l10n, it's possible to pass a cacheId option to the gulp-l10n.setLocales() and gulp-l10n() methods. The default cacheId is default.

var gulp = require('gulp');
var l10n = require('gulp-l10n');
 
gulp.task('load-locales-1', function () {
  return gulp.src('locales1/*.json')
    .pipe(l10n.setLocales('en', {
      cacheId: 'foo'
    }));
});
 
gulp.task('localize-1', ['load-locales-1'], function () {
  return gulp.src('src1/**/*.html')
    .pipe(l10n({
      cacheId: 'foo'
    }))
    .pipe(gulp.dest('dist/src1'));
});
 
gulp.task('load-locales-2', function () {
  return gulp.src('locales2/*.json')
    .pipe(l10n.setLocales('en', {
      cacheId: 'bar'
    }));
});
 
gulp.task('localize-2', ['load-locales-2'], function () {
  return gulp.src('src2/**/*.html')
    .pipe(l10n({
      cacheId: 'bar'
    }))
    .pipe(gulp.dest('dist/src2'));
});
 
gulp.task('default', ['localize-1', 'localize-2']);

API

The Node API as if the gulp-l10n plugin is assigned to the variable l10n.

var l10n = require('gulp-l10n');

l10n.extract()

Pipe html files to this method to semantically extract strings for translation.

This method clears the pipe and outputs only a single native locale – by default: en.json.

  // inside a gulp task:
 
  var options = {
    native: 'de',
    elements: ['title', 'p', 'h1', 'h2', 'h3', 'h4', 'h5', 'h6', 'test'],
    attributes: ['alt', 'title', 'test']
  };
 
  return gulp.src('**/*.html')
    .pipe(l10n.extract( options ))
    .pipe(gulp.dest('locales'));

Options

The l10n.extract() options object accepts all s18n extract options, as well as the gulp-l10n-specific options below.

native

• Accepts: String
• Default: 'en'

Set the locale code in which your website or application is authored. This is used in the file name of the native locale output by the method.

l10n.setLocales()

Pipe locales through this method before piping html through l10n().

  // inside a gulp task:
 
  var options = {
    native: 'de',
    cacheId: 'test'
  };
 
  return gulp.src('locales/*.json')
    .pipe(l10n.setLocales( options ));

Options

The l10n.setLocales() method accepts an options object.

native

• Accepts: String
• Default: 'en'

Set the s18n native locale. This is the locale in which your website or application is authored.

Default: 'en'

cacheId

• Accepts: String
• Default: 'default'

Set the locale cache in which the locale is saved. Allows for multiple distinct websites or applications to be separately translated by the same instance of gulp-l10n.

enforce

• Accepts: String
• Default: 'silent'

Set the enforcement mode.

Mode	Description
'silent'	Do not enforce localization.
'warn'	Warn about missing localizations.
'strict'	Throw error on missing localizations.

l10n()

Gulp plugin to localize html files using locales previously set with the setLocales method.

  // inside a gulp task:
 
  var options = {
    cacheId: 'test',
    hrefRewrite: function(href, locale){
      if(href.charAt(0) === '/'){
        return '/' + locale + href;
      }
      else {
        return href;
      }
    }
  };
 
  return gulp.src('**/*.html')
    .pipe(l10n( options ))
    .pipe(gulp.dest('dist'));

Options

The l10n() options object accepts all s18n localization options, as well as the gulp-l10n-specific options below.

cacheId

• Accepts: String
• Default: 'default'

Set the locale cache used in localizing html. Allows for multiple distinct websites or applications to be separately translated by the same instance of gulp-l10n.

hrefRewrite

• Accepts: Function(href, locale), null
• Default: null

A function to transform all hrefs in each html document localized. The value of each href will be replaced by the value returned by this function. Hrefs will not be rewritten if this option is set to null.

Parameter	Description
href	The original value of the href attribute currently being transformed.
locale	The locale code of the locale currently being applied to the html document. This is also the name of the current locale's directory. (Eg: en, de, etc.)

outPath

• Accepts: Function(base, path, localeId), string
• Default: return path.replace(base, base + localeId + '/');

A function to compute a custom output path for localized files.

Example for files of the form index.de.html

 
  gulp.task('localize', function () {
    return gulp.src('*.html')
      .pipe(l10n({
        outPath: function (base, path, localeId) {
          return path.slice(0, -4) + localeId + ".html";
        }
      }))
      .pipe(gulp.dest(pkg.release));
  });

Contributing

The default Gulp task watches all files and runs tests and code coverage.

$ npm install -g gulp
$ gulp

Testing

This module strives to maintain passing tests with 100% coverage in every commit, and tests are run pre-commit. If you prefer, you can always skip this check with git commit --no-verify and squash WIP commits for pull requests later.

If you're unsure or would like help writing tests or getting to 100% coverage, please don't hesitate to open up a pull request so others can help!