nebula-i18n | Vaadin

i18n localization with Airbnb Polyglot.

[ This description is mirrored from at on 2019-05-10 ]

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A set of web components to support i18n localization using Airbnb Polyglot. Components are included to match browser and application supported languages, load localized string resources, and integrate reactive string translations in your application.

Warning: This element utilizes the browser Fetch API which may not be supported by all browsers. To ensure support by all browsers, consider using the Fetch Polyfill.


$ bower install arsnebula/nebula-i18n

Getting Started

Import the package elements:

<link rel="import" href="/bower_components/nebula-i18n/nebula-i18n.html">

Add and configure a <nebula-language> element to compare the browsers supported languages to application supported languages, and select a preferred language. This will commonly be done once in your top-level application element.

  supported='["en-US", "en-CA", "en", "fr-CA", "fr"]'

Prepare your localized string resource files. Resources should be grouped by a BCP47 language code in JSON format. Each file can contain one or more language resources, although it is common to have a seperate file for each language. Localization strings can include variables, and support pluralization. For additional information on using variables and supporting pluralization in resources, please see the Polyglot API documentation.

  "en": {
    "greeting": "Hello"
  "fr": {
    "greeting": "Bonjour"
  "de": {
    "greeting": "Hallo"

Use the <nebula-resources> element to easily load resource files containing string translations. It is recommended you create a folder in your web root folder to contain your resource files. It is common to separate resources by language, and name the file with the language code. By binding the file property to the application language, it will load the appropriate application resources whenever the browser language is updated.


Add the Nebula.PolyglotBehavior to your elements to support localization. This will automatically add lang and resources properties to your element.

  is: 'my-element',
  behaviors: [

Update your element template to localize strings using the special $t computed function property, passing in a key, and additional options for variables or pluralization if necessary.


For more information, see the API documentation.


We welcome and appreciate feedback from the community. Here are a few ways that you can show your appreciation for this package:

  • Give us a Star on GitHub from either or directly on GitHub.

  • Submit a feature request, or a defect report on the Issues List.

  • Become a Patreon. It takes a lot of time and effort to develop, document, test and support the elements in our Nebula Essentials collection. Your financial contribution will help ensure that our entire collection continues to grow and improve.

If you are a developer, and are interested in making a code contribution, consider opening an issue first to describe the change, and discuss with the core repository maintainers. Once you are ready, prepare a pull request:

  1. Fork it!
  2. Create your feature branch: git checkout -b my-new-feature
  3. Commit your changes: git commit -am 'Add some feature'
  4. Push to the branch: git push origin my-new-feature
  5. Submit a pull request :D

Change Log





Link to this version
ImportedReleased 29 January 2018ISC License
Framework Support
Polymer 2.0+
Also supported:
Polymer 1 (2.0.0)
Browser Compatibility
Install with
bower install --save arsnebula/nebula-i18n"#2.0.2"
Run the above Bower command in your project folder. If you have any issues installing, please contact the author.
Release notes - Version 2.0.2


  • polymer#Polymer/polymer#^2.0.0
  • nebula-element-mixin#arsnebula/nebula-element-mixin#^2.0.0
  • polyglot#airbnb/polyglot.js#^2.2.2