Angular i18n

13 Nov 2017

Target Audience

It is just quick startup guide for programmers who already know the concept from below link:


Setup Angular project

For JIT compilation

  1. Add LOCALE_ID in app.module.ts

import { LOCALE_ID} from '\@angular/core';

  1. Add provider in app.module.ts

providers: [ { provide: LOCALE_ID, useValue: 'fr' } ],

  1. Add locales like below in app.module.ts. En-US locale is provided by default.

import { registerLocaleData } from '\@angular/common';

import localeFr from '\@angular/common/locales/fr';


  1. Run below command to generate xlf file. File would be generated at src/locale folder by default.

ng xi18n –outputPath src/locale

By default, the tool generates a translation file named messages.xlf

You can specify the translation format explicitly with the --i18nFormat flag as illustrated in these example commands:

ng xi18n --i18nFormat=xlf ng xi18n --i18nFormat=xlf2 ng xi18n --i18nFormat=xmb

  1. Make copies of message.xlf file like and and node corresponding to source nodes manually for testing. You can also use XLIFF file editor.

  2. Add below code in main.ts

//use the require method provided by webpack

declare const require;

//we use the webpack raw-loader to return the content as a string

const translations = require(`raw-loader!./locale/`);

platformBrowserDynamic().bootstrapModule(AppModule, {

providers: [

{ provide: TRANSLATIONS, useValue: translations },

{ provide: TRANSLATIONS_FORMAT, useValue: 'xlf' }


}) .catch(err => console.log(err));

  1. Run the project. It will run your project in France (fr) language.

For AOT compilation

  1. follow step 4 for JIT compilation

  2. Run project with below command.

ng serve --aot --i18nFile=src/locale/ --i18nFormat=xlf --locale=fr

Change the file and format as per your case

Note: you can keep the lengthy commands in packages json script to remember.


The i18n template translation process has four phases:

  1. Mark static text messages in your component templates for translation.

  2. An Angular i18n tool extracts the marked text into an industry standard translation source file.

  3. A translator edits that file, translating the extracted text into the target language, and returns the file to you.

  4. The Angular compiler imports the completed translation files, replaces the original messages with translated text, and generates a new version of the app in the target language.

You need to build and deploy a separate version of the app for each supported language.