aurelia-i18n

This library is part of the Aurelia platform and contains a plugin that provides i18n support. Under the hood it uses the i18next library.

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How to install this plugin?
How to use this plugin
Internationalization API Polyfill
Usage with webpack
CLI Integration
Migration to new i18next version
Polyfills
Dependencies
Used By
Platform Support
Building The Code
Running The Tests

How to install this plugin?

In your project install the plugin via jspm with following command
```
jspm install aurelia-i18n
```
Make sure you use manual bootstrapping. In order to do so open your index.html and locate the element with the attribute aurelia-app. Change it to look like this:
```
<body aurelia-app="main">
...
```
Create folder locale in your projects root
For each locale create a new folder with it's name (e.g. en, de, ...)

In those subfolders create a file named translation.json which contains your language specific translations. Below you can find a sample en-EN translation file. The full potential of i18next is achieved through a specific translation-file schema. Consult the i18next docs to find out more about it.

{
    "score": "Score: {{score}}",
    "lives": "{{count}} life remaining",
    "lives_plural": "{{count}} lives remaining",
    "lives_indefinite": "a life remaining",
    "lives_plural_indefinite": "some lives remaining",
    "friend": "A friend",
    "friend_male": "A boyfriend",
    "friend_female": "A girlfriend"
}

NEW!: Install a backend plugin From v.2 you have to pick your own backend service. For this guide we're going to leverage the XHR Plugin Install it in the root of your project via jspm install npm:i18next-xhr-backend.

Create (if you haven't already) a file main.js in your src folder with following content:

import {I18N} from 'aurelia-i18n';
import Backend from 'i18next-xhr-backend'; // <-- your previously installed backend plugin

export function configure(aurelia) {
    aurelia.use
      .standardConfiguration()
      .developmentLogging()
      .plugin('aurelia-i18n', (instance) => {
        // register backend plugin
        instance.i18next.use(Backend);

        // adapt options to your needs (see http://i18next.com/docs/options/)
        // make sure to return the promise of the setup method, in order to guarantee proper loading
        return instance.setup({
          backend: {                                  // <-- configure backend settings
            loadPath: '/locales/{{lng}}/{{ns}}.json', // <-- XHR settings for where to get the files from
          },
          lng : 'de',
          attributes : ['t','i18n'],
          fallbackLng : 'en',
          debug : false
        });
      });

    aurelia.start().then(a => a.setRoot());
}

You may also group your translations by namespaces, spread across multiple files. Say you have the standard translation.json and an additional nav.json for the navigation items, you can configure aurelia-i18n by passing the ns setting in the config object containing the different namespaces as well as the default namespace.

instance.setup({
  ...
  ns: {
    namespaces: ['translation','nav'],
    defaultNs: 'translation'
  }
});

If You use typescript

Unfortunately creators of i18next and i18next-xhr-backend have not yet provided typings for these libraries for now. So, during the typescript compilation process you will see the following error messages:
```
"/yourHost/pathToApp/pathToFile/filename.ts(3,26): Cannot find module 'i18next-xhr-backend'."
"/yourHost/pathToApp/jspm_packages/npm/aurelia-i18n@0.5.2/aurelia-i18n.d.ts(2,23): Cannot find module 'i18next'."
```
In order to fix that you first need to get the *.d.ts files:
1. i18next
  - If You use typings (it is most likely true) you can istall typings for i18next with next command in console:
```
typings install i18next --ambient
```
  - alternatively you can use a similar file from this repositories doc folder (doc/i18next.d.ts)
2. i18next-xhr-backend
  - use the typings file from this repositories doc folder doc/i18next-xhr-backend.d.ts
in order to comply with some neat project structure you should copy *.d.ts files from doc/*.d.ts to another folder, e.g. /customTypings

The next step is to let the compiler know about your *.d.ts files. Add the following section to your tsconfig.json file.
```
// ... existing configuration code
"filesGlob": [
    "./typings/browser.d.ts", // this must be specified in case you use typings(https://github.com/typings/typings)
    "./your_custom_typings_folder_path/**/*.d.ts", // if you use both typings files from this repository (`doc/*.d.ts`)
  ],
// ... other existing configuration code
```

How to use this plugin

i18next translations work by setting up an active locale, which you've setup above in the init phase with the property lng.

Setting the active locale

In order to change the active language you'd have to call the function setLocale(localeName) via code.

import {I18N} from 'aurelia-i18n';

export class MyDemoVM {
	static inject = [I18N];
	constructor(i18n) {
	  this.i18n = i18n;
		this.i18n
		    .setLocale('de-DE')
		    .then( () => {
			// locale is loaded
		});
	}
	...
}

Getting the active locale

To get the active locale you'd go with getLocale():

import {I18N} from 'aurelia-i18n';

export class MyDemoVM {
	static inject = [I18N];
	constructor(i18n) {
	   this.i18n = i18n;
		 console.log(this.i18n.getLocale());
	}
	...
}

Translating via code

Translating stuff via code works by using the method tr. You pass in the key as first parameter, followed by the optional second parameter options to specify in detail how the translations should be performed. Please consult the i18next docs for a detailed list of those:

import {I18N} from 'aurelia-i18n';

export class MyDemoVM {
	static inject = [I18N];
	constructor(i18n) {
	   this.i18n = i18n;
		 console.log(this.i18n.tr('mykey'));
	}
	...
}

Translating via html attributes

Translation in html can be done alternatively using attributes. By default the plugin is configured to use the t and i18n attributes. This can be configured during the plugin registration using the attributes property.

...
instance.setup({
	...
	attributes : ['t','i18n'],
	...
});
...

Any element in your views that has one of those attributes, will be translated when the locale is changed.

<span t="title">Title</span>

The plugin will use the title as the key when translating that element. Other attributes, specified in the attributes option, may be used as well.

<span i18n="home.title">Title</span>

Notice in the above example that the key was set to home.title. This will make the plugin look for a translation with nested objects in your translation json, ie:

{
  "home": {
    "title": "Title",
  }
}

Use updateTranslation() to update all translations within the children of the element that is passed to it. The following example shows how a view model can be configured to update it's contents when the view is attached and every time a locale is changed.

import {I18N} from 'aurelia-i18n';
import {EventAggregator} from 'aurelia-event-aggregator';

export class MyDemoVM {
  static inject = [I18N,Element,EventAggregator];
  constructor(i18n,element,ea) {
    this.i18n = i18n;
    this.element = element;

	  ea.subscribe('i18n:locale:changed', payload => {
	    this.i18n.updateTranslations(this.element);
	  });
  }

  attached(){
    this.i18n.updateTranslations(this.element);
  }
}

Alternatively you may extend your VM with the provided Base-I18N-VM, which will set that up for you automatically.

import {BaseI18N} from 'aurelia-i18n';

export class MyDemoVM extends BaseI18N {

}

Just remember in case you define your own constructor, to call this.super and pass it the instances of its dependencies as described in the previous example. Same applies to attached, although nothing needs to be passed in here

Specifying attributes

By default the plugin will set the textContent property of an element.

//translation
{
  "title": "Title <b>bold</b>"
}

//markup
<span t="title">Title</span>

So in above example the html tags will be escaped and the output will be <b>bold</b>. To allow html-markup to be used, the [html] attribute needs to be added before the translation key.

<span t="[html]title">Title</span>

This will set the innerHTML of the element instead of the textContent property, so html-markup won't be escaped. There are 4 special attributes including the shown [html]:

[text]: Sets the textContent property (default)
[html]: Sets the innerHTML property
[append]: appends the translation to the current content already present in the element (allows html).
[prepend]: prepends the translation to the current content already present in the element (allows html).

Any other values will be used as actual attributes on the element. The following example will not change the content of the element, but will set its alt attribute to the translated value of title when the locale changes.

<span t="[alt]title">Title</span>

Specifying multiple attributes

Multiple attributes can be specified by separating them with a semicolon.

<span t="[html]title;[class]title-class">Title</span>

When the locale changes it will set the innerHTML to the translated value of title due to the [html] attribute and the class property to the translated value of title-class.

Using nested and combined translations

In order to combine two or more translations, just include them with the $t(yourkey) markup

<span t="$t(title) $t(subtitle)">Title subtitle</span>

Nested keys may also be referenced and will be properly translated:

{
  "translation": {
    "title": "Title",
    "nested_referencing": 'The $t(title) is the header',
    ...
  }
}

<span t="nested_referencing">Nested text</span>

Translating images

Images can be translated as well, for when a different image needs to be displayed in another language.

<img t="home.image" />

The plugin will automatically change the src attribute of the image when the locale changes.

You may specify a default value for images as well. In order to do so just define an attribute called data-src with the default value.

<img data-src="path/to/image.jpg" t="home.image" />

This will be picked up by the CLI when translations are extracted from the source files. (see the section on CLI Integration)

Passing parameters to the attribute

In order to use parameters for replaceable parts in your translation key, you can provide an additional t-params attribute and bind it to the object containing the replacement values. Also note that for whatever attribute you registered, the corresponding *-params attribute will get registered as well automatically.

// Translation file
{
  "paramstest": "Some text with <strong>{{content}}</strong>"
}

<!-- View -->
<span t="[html]paramstest" t-params.bind="params"></span>

// ViewModel
class MyVM {
  params = { content: 'ABC' }

  [...]
}

The object passed to t-params is a complex object explained in the next section

Translating with the TValueConverter

In order to do translations in a more declarative way from within your HTML markup you can use a custom ValueConverter named t. It takes exactly the same options as the code translation method tr but of course provides the key automatically.

You will find below a few examples of the available i18next features

<template>
  <section>
    <div class="row">
      <div class="col-md-3">
        <h3>ValueConverter Examples</h3>
        <ul class="list-group">
          <li class="list-group-item">
            Translation with Variables: <br />
            ${ 'score' | t: {'score': userScore}}
          </li>

          <li class="list-group-item">
            Translation singular: <br />
            ${ 'lives' | t: { 'count': 1 } }
          </li>

          <li class="list-group-item">
            Translation plural: <br />
            ${ 'lives' | t: { 'count': 2 } }
          </li>

          <li class="list-group-item">
            Translation singular indefinite: <br />
            ${ 'lives' | t: { 'count': 1, indefinite_article: true  } }
          </li>

          <li class="list-group-item">
            Translation plural indefinite: <br />
            ${ 'lives' | t: { 'count': 2, indefinite_article: true } }
          </li>

          <li class="list-group-item">
            Translation without/with context: <br />
            ${ 'friend' | t } <br />
            ${ 'friend' | t: { context: 'male' } } <br />
            ${ 'friend' | t: { context: 'female' } }
          </li>
        </ul>
      </div>
    </div>
  </section>
</template>

Translating with the TBindingBehavior

The TValueConverter is pretty useful if you prefer a declarative way to enhance DOM elements with i18n support. But it has a lack when it comes to automatically updating itself when changes happen outside, like locale switches. This is what the TBindingBehavior can do. Essentially you do the same thing like with the TValueConverter but use the & #stead of | to indicate usage of the binding behavior.

<li class="list-group-item">
  Translation with Variables: <br />
  ${ 'score' & t: {'score': userScore}}
</li>

Now aurelia-i18n will automatically emit signals when internal changes happen and you can do so as well by emiting a aurelia-translation-signal. The following example depicts how this is done internally when the current locale changes. First you need to get hold of the BindingSignaler exported by the aurelia-templating-resources module and inject it either in your constructor or via the static $inject property. Next when you want to trigger the signal just use the signalers signal method and pass it the predefined string.

import {BindingSignaler} from 'aurelia-templating-resources';
// inject signaler to constructor ...
...

setLocale(locale) {
  return new Promise( resolve => {
    let oldLocale = this.getLocale();
    this.i18next.setLng(locale, tr => {
      this.ea.publish('i18n:locale:changed', { oldValue: oldLocale, newValue: locale });
      this.signaler.signal('aurelia-translation-signal');
      resolve(tr);
    });
  });
}

Complex objects for variables

In some cases it might be useful to define variables via complex objects. Let's take a look at below example. It shows a validation message to hint the user that a given field should be in range of min and max. Now we could easily pass min and max as separate variables but on the other hand that involves more work you'd have to do manually if the source is a object.

var resources = {
  en: {
    translation: {
      "complex": '{{field}} should be between {{threshold.min}} and {{threshold.max}}'
    }
  }
};

So in order to avoid that you may simply pass in the object as a whole and the library will pickup all the necessary information and create the proper options object. You can also mix and match it with simple variables.

var options = {
  'threshold': {
    'min': 1,
    'max': 10
  },
  'field': 'Age'
};

i18n.tr('complex', options);
// --> Age should be between 1 and 10

Formatting numbers via code

For displaying numbers in different formats, this plugin makes use of the Internationalization API NumberFormat. It leverages the same locales used for the translation methods mentioned in the install process of the plugin.

The API provides access to the Intl NumberFormat with the method NumberFormat. This function takes the an options object representing the formatting options as the first and the locale as the second parameter.

Below is an example how to access the NumberFormat via code:

import {I18N} from 'aurelia-i18n';

export class MyDemoVM {
  static inject = [I18N];
	constructor(i18n) {
	  this.i18n = i18n;

	  // create a NumberFormat with German locale
    var nf = this.i18n.nf(undefined, 'de');
	  var result = nf.format(123456.123);

	  console.log(result);
	  // output => 123.456,123


	  // create a NumberFormat with currency options
	  var nf = this.i18n.NumberFormat({ style: 'currency', currency: 'EUR' }, 'de');

	  var result = nf.format(123456.123);

	  console.log(result);
	  // output => 123.456,123 �  	  
	}
	...
}

Formatting numbers with NfValueConverter

A more declarative way is to use the nf ValueConverter from within your HTML markup. It essentially works the same way as the code version. Take a look at the following example:

<div class="col-md-3">
  <h3>ValueConverter Number Examples</h3>
  <ul class="list-group">
    <li class="list-group-item">
      Numberformat with default locale/format:
      ${ 1234567.890 | nf : undefined : selectedLocale}
    </li>
    <li class="list-group-item">
      Numberformat with different locale default format:
      ${ 1234567.890 | nf : undefined : 'de'}
    </li>
    <li class="list-group-item">
      Numberformat with different locale/format:
      ${ 1234567.890 | nf : { style: 'currency', currency: 'EUR' } : 'de'}
    </li>
  </ul>
</div>

Note that if you provide the active locale as a bound VM property, the ValueConverter will be re-evaluated as soon as the property value changes, resulting in automatic re-formatting of your number.

Formatting dates via code

The Intl. API provides means to format DateTimes as well. Use the method df to access that feature with the same arguments used for NumberFormat Below you'll find an example how to use those via code:

import {I18N} from 'aurelia-i18n';

export class MyDemoVM {
  static inject = [I18N];
	constructor(i18n) {
	  this.i18n = i18n;

	  // create a DateTimeFormat with German locale
    var df = this.i18n.df(undefined, 'de');
	  var result = df.format(new Date(2000, 0, 1, 0,0,1))

	  console.log(result);
	  // output => 1.1.2000


	  // create a DateTime with time and 2-digit display
	  var options = {
      year: 'numeric', month: '2-digit', day: '2-digit',
      hour: '2-digit', minute: '2-digit', second: '2-digit',
      hour12: false
    };
	  var df = this.i18n.df(options, 'de');

	  var result = df.format(new Date(2000, 0, 1, 0,0,1));

	  console.log(result);
	  // output => 01.01.2000 00:00:01  	  
	}
	...
}

Remember that if you pass in undefined for the options parameter you'll get the default formatting options

Formatting dates with DfValueConverter

A more declarative way is to use the df ValueConverter from within your HTML markup. It essentially works the same way as the code version. Take a look at the following example, which defines a VM property myDate:

<div class="col-md-3">
  <h3>ValueConverter Date Examples</h3>
  <ul class="list-group">
    <li class="list-group-item">
      DateFormat with default locale/format:
      ${ myDate | df : undefined : selectedLocale}
    </li>
    <li class="list-group-item">
      DateFormat with different locale default format:
      ${ myDate | df : undefined : 'de'}
    </li>
    <li class="list-group-item">
      DateFormat with different locale/format:
      ${ myDate | df : { weekday: 'long', year: 'numeric', month: 'long', day: 'numeric' } : 'de'}
    </li>
  </ul>
</div>

Rendering relative time

In order to create a representation of relative time like x days ago or in x days you can leverage the Service relativeTime. This exposes a method getRelativeTime which accepts a valid JS date. To use it via code get hold of the service via injection and call the method as needed:

import {RelativeTime} from 'aurelia-i18n';

export class MyDemoVM {
  static inject = [I18N];
	constructor(relativeTime) {
	  this.rt = relativeTime;

	  var myDate = new Date();
    myDate.setHours(myDate.getHours() - 2);

	  console.log(result);
	  // output => 2 hours ago  	  
	}
	...
}

This is also tied in to the currentLocale of the library so changing that one will also translate relative time messages. Take a look at the file src/defaultTranslations/relative.time.js for available translations. If you're missing yours I welcome you to provide a PR so everybody can benefit from it.

A more declarative approach is to use the RtValueConverter directly in your HTML markup. It's not taking any additional parameters so just drop it in and you're good to go:

<div class="col-md-3">
  <h3>ValueConverter Relative Time Examples</h3>
  <ul class="list-group">
    <li class="list-group-item">
      2 hours ago:
      ${ myDate | rt }
    </li>
  </ul>
</div>

Internationalization API Polyfill

The plugin leverages the JavaScript Internationalization API to perform certain tasks. Since not all browsers do fully support it (compatibility table) the aurelia-i18n conditionally loads the Polyfill if needed.

In case of bundling your app you should thus keep in mind that it will not be automatically included into the bundle. That means you have to manually adjust the bundle config to include the polyfill as well, if you intend to have your application run on browsers without full support. related GitHub issue

Usage with webpack

This library has more than one file that needs to be resolved. But by default, only the main file is loaded. Which means that you will get a error like:

.*$:106 Uncaught (in promise) Error: Cannot find module './aurelia-i18n/t'.
.*$:106 Uncaught (in promise) Error: Cannot find module './aurelia-i18n/nf'.
.*$:106 Uncaught (in promise) Error: Cannot find module './aurelia-i18n/df'.
Uncaught (in promise) Error: Cannot find module './aurelia-i18n/rt'.

To correct this, you must, as described in the aurelia-webpack-plugin documentation, use the includeSubModules option in the configuration of the AureliaWebpackPlugin:

new AureliaWebpackPlugin({
  includeSubModules: [
    { moduleId: "aurelia-i18n" }
  ]
})

On top of that if you need the Intl polyfill included you have to manualy require and bundle it. To do so add the following import statement at the begin of your main.js/ts file:

//main.js
import 'intl';

For additional information about Intl.js and Webpack please take a look at this official repos information

CLI Integration

There will be a command line tool that can create translation.json files for you by extracting the values from the html and javascript files. (coming soon)

Migration to new i18next version

Default interpolation is {{ and }} instead of __
API Changes: Keep those in mind if you accessed the original i18next object and performed custom actions the existing aurelia-i18n methods have been updated to use the new API
Options removed/changed: { sendMissing, getAsync, resStore => resources }
plural_not_found won't be thrown but the given key if no plural is defined
indefinite plural was removed in v2 (I have 1 apple -> I have one apple)
No default backend

The new version requires the user to define its own backend service. This was done in order to keep the core clean and easily upgradable. So from now on users of aurelia-i18n also need to setup their own backend service. In order to do so we can leverage a i18next plugin from this list- Take a look at the updated How to install this plugin? section.

Polyfills

andyearnshaw/Intl.js

Platform Support

This library can be used in the browser only.

Building The Code

To build the code, follow these steps.

Ensure that NodeJS is installed. This provides the platform on which the build tooling runs.
From the project folder, execute the following command:

npm install

Ensure that Gulp is installed. If you need to install it, use the following command:

npm install -g gulp

To build the code, you can now run:

gulp build

You will find the compiled code in the dist folder, available in three module formats: AMD, CommonJS and ES6.
See gulpfile.js for other tasks related to generating the docs and linting.

Running The Tests

To run the unit tests, first ensure that you have followed the steps above in order to install all dependencies and successfully build the library. Once you have done that, proceed with these additional steps:

Ensure that the Karma CLI is installed. If you need to install it, use the following command:

npm install -g karma-cli

Ensure that jspm is installed. If you need to install it, use the following commnand:

npm install -g jspm

Install the client-side dependencies with jspm:

jspm install

You can now run the tests with this command:

karma start

Name		Name	Last commit message	Last commit date
Latest commit History 142 Commits
build		build
dist		dist
doc		doc
src		src
test/unit		test/unit
.editorconfig		.editorconfig
.eslintrc		.eslintrc
.gitignore		.gitignore
.npmignore		.npmignore
CONTRIBUTING.md		CONTRIBUTING.md
LICENSE		LICENSE
README.md		README.md
bower.json		bower.json
config.js		config.js
gulpfile.js		gulpfile.js
karma.conf.js		karma.conf.js
package.json		package.json

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Repository files navigation

aurelia-i18n

How to install this plugin?

How to use this plugin

Setting the active locale

Getting the active locale

Translating via code

Translating via html attributes

Specifying attributes

Specifying multiple attributes

Using nested and combined translations

Translating images

Passing parameters to the attribute

Translating with the TValueConverter

Translating with the TBindingBehavior

Complex objects for variables

Formatting numbers via code

Formatting numbers with NfValueConverter

Formatting dates via code

Formatting dates with DfValueConverter

Rendering relative time

Internationalization API Polyfill

Usage with webpack

CLI Integration

Migration to new i18next version

Polyfills

Platform Support

Building The Code

Running The Tests

About

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krostkowski/i18n

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aurelia-i18n

How to install this plugin?

How to use this plugin

Setting the active locale

Getting the active locale

Translating via code

Translating via html attributes

Specifying attributes

Specifying multiple attributes

Using nested and combined translations

Translating images

Passing parameters to the attribute

Translating with the TValueConverter

Translating with the TBindingBehavior

Complex objects for variables

Formatting numbers via code

Formatting numbers with NfValueConverter

Formatting dates via code

Formatting dates with DfValueConverter

Rendering relative time

Internationalization API Polyfill

Usage with webpack

CLI Integration

Migration to new i18next version

Polyfills

Platform Support

Building The Code

Running The Tests

About

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License

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