Angular

Localize Angular apps with Transifex Native

You can easily localize Angular components using the @transifex/angular library extension. This library extends the functionality of Transifex Native JavaScript SDK.

Related packages:

Installation

Install the extension library using:

npm install @transifex/native @transifex/angular @transifex/cli --save

Supported versions are Angular 12 & 13. For Angular 11 please use the 1.x.x versions of the @transifex/angular npm package. Other Angular versions are not officially supported at the moment.

Initialization

In order to use the TX Native object globally, it is necessary to initialize the library in the angular application bootstrap, in two locations:

  • NgModule initialization
@NgModule({
  declarations: [
    AppComponent,
    LoginComponent,
    TermsComponent,
    HomeComponent,
    PrivacyComponent
  ],
  imports: [
    AppRoutingModule,
    BrowserModule,

    // TX Native module declaration
    TxNativeModule.forRoot(),
  ],
  providers: [,
  ],
  bootstrap: [AppComponent]
})

  • Application Boostrap
import { Component } from '@angular/core';
import { TranslationService } from '@transifex/angular';

@Component({
  selector: 'app-root',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.scss']
})
export class AppComponent {
  constructor(private translationService: TranslationService) {
    // TX Native library intialization
    translationService.init({
      token: '----- here your TX Native token ------',
    });
  }

  async ngOnInit() {
    await this.translationService.getLanguages();
    await this.translationService.setCurrentLocale('el');
  }
}

Usage

T Component

Use the T component to mark strings for translation based on the example below.

  <p>
    <label>
      <T str="Password" key="label.password"></T>
    </label>
    <input type="password" name="password" />
  </p>

Prop

Type

Description

str

String

Source string

context

String

String context, affects key generation

key

String

Custom string key

comment

String

Developer comment

charlimit

Number

Character limit instruction for translators

tags

String

Comma separated list of tags

escapeVars

Boolean

If escaping should be applied to ICU variables

sanitize

Boolean

Safe render of the HTML result after translation takes place

vars

Object

ICU variables to render in the string

The T component can sanitize the translated result if HTML is involved, using the parameter sanitize, ie this would be possible:

  <p>
    <T
      str="By proceeding you agree to the {terms_of_services} and {privacy_policy}."
      key="text.agree_message"
      [sanitize]=true
      [vars]="{ terms_of_services: '<a href=\'terms\'>' + terms + '</a>',
        privacy_policy: '<a href=\'privacy\'>' + privacy + '</a>'
      }">
    </T>
  </p>

This will render like this in English:

<span>By proceeding you agree to the <a href="terms">terms of service</a> and <a href="privacy">privacy policy</a>.</span>

And like this in Greek:

<span>Συνεχίζοντας, αποδέχεστε τους <a href="terms">όροι χρήσης</a> και τους <a href="privacy">πολιτική απορρήτου</a>.</span>

The same block without the sanitize option would be like this, for Greek:

Συνεχίζοντας, αποδέχεστε τους &lt;a href='terms'&gt;όροι χρήσης&lt;/a&gt; και τους &lt;a href='privacy'&gt;πολιτική απορρήτου&lt;/a&gt;.

📘

The main thing to keep in mind is that the str property to the T component must always be a valid ICU message format template.

If it is nested into a tx-instance tag, then the T component will use the new instance to fetch the translation. Check the TX Instance Component section for more information about additional instances.

UT Component

UT component has the same behavior as T component, but renders source string as HTML inside a div tag or a span tag if inline property is true.

Available optional props are the same as the T component but has escapeVars property enabled by default, and:

Prop

Type

Description

inline

Boolean

If should wrap the translation with span (true) of with a div (default, if false)

If it is nested into a tx-instance tag, then the UT component will use the new instance to fetch the translation. Check the TX Instance Component section for more information about additional instances.

TranslationService service

This is the main service exposed from the SDK in order to intialize the TX Native object.

In your bootstrap entry point in the Angular application, you should initialize the SDK, like this:

import { Component } from '@angular/core';
import { TranslationService } from '@transifex/angular';

@Component({
  selector: 'app-root',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.scss']
})
export class AppComponent {
  title = 'TX Native Angular Demo';

  constructor(private translationService: TranslationService) {
    translationService.init({
      token: '----- here your TX Native token ------',
    });
  }

  async ngOnInit() {
    await this.translationService.getLanguages();
    await this.translationService.setCurrentLocale('el');
  }
}

The translation service is a singleton instance so the initialization will be shared across the whole application.

It keeps also a collection of additional TX Native instances which can be added to the default instance for specific purposes.

Each addional instance should have the following configuration:

ITXInstanceConfiguration {
  token: string;
  alias: string;
  controlled: boolean;
}

See the section TX Instance Component for more details.

The additional instances can be added and retrieved using exposed methods addInstance and getInstance.

The translation service also offers the possibility to retrieve translations that match a given list of tags, this way it's possible to fetch groups of translations in batches, at different times or for lazy loading. This can be achieved using the fetchTranslations method.

Exposes the following methods and properties:

Method

Parameters

Description

init

config ¹

Initializes the TX Native object

setCurrentLocale

locale ²

Set the current locale in the TX Native object

getCurrentLocale

none

Returns the current locale of the TX Native

getLanguages

none

Returns an array of available languages

translate

translate params (2)

Returns the translation for a string with given translation params

localeChanged

none

Returns an observable for monitoring the locale changed event

translationsFetched

none

Returns an observable for monitoring the fetch translations event

addInstance

ITXInstanceConfiguration

Returns true if the new TX Native instance was added succesfully and false otherwise

getInstance

string

Returns the TX Native instance with the given alias. If the operation is not possible the default one is returned as fallback.

fetchTranslations

array

Returns a collection of translations that match a given list of tags.

(1) Initialization config

export interface ITranslationServiceConfig {
  token: string;
  cdsHost?: string;
  filterTags?: string;
  cache?: () => void;
  missingPolicy?: IPolicy;
  errorPolicy?: IPolicy;
  stringRenderer?: IStringRenderer;
}
  • cache, missingPolicy, errorPolicy and stringRenderer are set by default by
    @transifex/native package but you can provide if you wish custom functions
    of your own, or use another policy provided by the @transifex/native package.

Please check the documentation related to this on@transifex/native package here.

(2) Translation params

str: string // string to be translated
params: Record<string, unknown> // an object with the params and variables

The params should follow the interface:

export interface ITranslateParams {
  _context?: string;
  _comment?: string;
  _charlimit?: number;
  _tags?: string;
  _key?: string;
  _escapeVars?: boolean;
  _inline?: boolean;
  sanitize?: boolean;
}

@T Decorator

This is a decorator for using inside classes and components in order to have
properties with the translation and used them in code and templates.

An example of use is the following:

import { Component, OnInit } from '@angular/core';
import { Router } from '@angular/router';
import { T, TranslationService } from '@transifex/angular';

@Component({
  selector: 'app-login',
  templateUrl: './login.component.html',
  styleUrls: ['./login.component.scss']
})
export class LoginComponent implements OnInit {
  // Translations using decorator
  @T('Monday', { _key: 'text.monday' })
  weekday: string;
  @T('terms of service', { _key: 'text.terms_of_service' })
  terms: string;
  @T('privacy policy', { _key: 'text.privacy_policy' })
  privacy: string;

  constructor(
    private translationService: TranslationService,
    private router: Router) {}

  login() {
    this.router.navigateByUrl('home');
  }
}

and the use of the properties in the template:

  <p>
    <T
      str="By proceeding you agree to the {terms_of_services} and {privacy_policy}."
      key="text.agree_message"
      [sanitize]=true
      [vars]="{ terms_of_services: '<a href=\'#/terms\'>' + terms + '</a>',
        privacy_policy: '<a href=\'#/privacy\'>' + privacy + '</a>'
      }"
    ></T>
  </p>

An instance configuration can be passed to the decorator in order to use an alternative instance instead of the main TX Native one.

See TX Instance Component for more information.

Example of alternative instance:

const INSTANCE_CONFIG = {
  token: 'XXXXXXXXXXXXXXXXXXXXXXXXXXXX',
  alias: 'mycmppage',
  controlled: true,
};

@Component({
  selector: 'my-component',
  templateUrl: './my.component.html',
  styleUrls: ['./my.component.scss']
})
export class MyComponent implements OnInit {
  @T('My string', { _key: 'text.my_string' }, INSTANCE_CONFIG)
  myString: string;

translate Pipe

You have available a translate pipe for inline strings translations, the only limitation that it has is that
you cannot translate strings with embedded HTML.

These examples will work:

  {{ 'Copyright {year} by Transifex' | translate:{ _key: 'text.copyright' } }}

  <p [matTooltip]="'A paragraph' | translate">A paragraph</p>

this example will not work, as it has HTML embedded:

  {{ 'A string with <b>HTML embedded</b>' | translate }}

If it is nested into a tx-instance tag, then the pipe will use the new instance to fetch the translation. Check the TX Instance Component section for more information about additional instances.

Language Picker Component

Renders a <select> tag that displays supported languages and switches the
application's selected language on change.
Uses Translation Service internally.

The html selector is tx-language-picker.

This is an example of use for the language picker component:

<tx-language-picker
  className="placeBottomLeft"
  (localeChanged)="onLocaleChanged($event)"></tx-language-picker>

and the event for locale changed inside the component could be:

import { Component, OnInit } from '@angular/core';
import { Router } from '@angular/router';
import { T, TranslationService } from '@transifex/angular';

@Component({
  selector: 'app-login',
  templateUrl: './login.component.html',
  styleUrls: ['./login.component.scss']
})
export class LoginComponent implements OnInit {
  onLocaleChanged(event) {
    // here we can do any action when locale changes
  }
}

Accepts properties:

  • className: The CSS class that will be applied to the <select> tag

Returns:

  • localeChanged: event for handling the change of locale

You always can implement a language picker of your choice, injecting
the TranslationService and using the different methods provided,
such as getLanguages.

TX Instance Component

Creates a new TX Native instance with the given configuration and adds it to the TX Native main instance. All the nested components will use the new instance in order to fetch the translations. This apply to components:

  • T/UT
  • translate pipe

Uses Translation Service internally to add the instance.

The html selector is tx-instance.

This is an example of use for the instance component:

this.instanceConfig = {
      token: 'XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX',
      alias: 'homepage',
      controlled: true,
    };
<tx-instance
  [token]="instanceConfig?.token"
  [alias]="instanceConfig?.alias"
  [controlled]="instanceConfig?.controlled"
  (instanceReady)="onInstanceReady($event)"
>
  <T str="My brand new string"></T>
</tx-instance>

Accepts properties:

  • token: The token for the new instance.
  • alias: A string indetifier of the instance, should be unique. If the identifier already exists, the existing instance with the given alias is used, and no new instance is created.
  • controlled: If the new instance is controlled (locale) by the main TX Native instance.

Returns:

  • instanceReady: event for handling the readiness of the new instance.

Exposes:

  • instanceIsReady: observable for listening the readiness of the new instance.

txLoadTranslations Directive

This directive can be used within any html or angular tag in order to force a group of translations to be fetched, using a list of tags to retrieve the translations that match.

This is an example of use:

  <p class="small-text" [txLoadTranslations]="'menu'">
    <a href="#/home">
      <UT str="home" key="text.home" inline=true></UT>
    </a>
    <a href="#/terms">
      <UT str="terms of service" key="text.terms_of_service" inline=true></UT>
    </a>
    <a href="#/privacy">
      <UT str="privacy policy" key="text.privacy_policy" inline=true></UT>
    </a>
    <a class="align-right" href="#/login">
      <UT str="logout" key="text.logout" inline=true></UT>
    </a>
  </p>

All the translations with the tag menu will be fetched using the current selected locale and instance, if the translations are already cached, they are not fetched again.

This way we can fetch the translations related with the part of the component's template when the component is first used and not from the beginning when instance is initialized (in the initialization we can use the filterTags param in order to fetch an initial set of translations and then use the lazy loading and improve the performance).


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