Category Archives: angular2

i18n angular2 service

This days I’m learning angular2 and ionic2. My first impression was bad. Too many new things: angular2, typescript, new project architecture, … but after passing those bad moments I started to like angular2. One of the first things that I want to work with is internationalization. There’re several i18n providers for angular2. For example ng2-translate, but I want to build something similar to a angular i18n provider that I’d created time ago.

The idea is first configure the service

import {Component} from "@angular/core";
import {Platform, ionicBootstrap} from "ionic-angular";
import {StatusBar} from "ionic-native";
import {HomePage} from "./pages/home/home";
import {I18nService} from "./services/i18n/I18nService";
import {lang} from "./conf/conf";

    template: '<ion-nav [root]="rootPage"></ion-nav>'
export class MyApp {
    rootPage:any = HomePage;

    constructor(platform:Platform, i18n:I18nService) {
        platform.ready().then(() => {

ionicBootstrap(MyApp, [I18nService]);

We can see that we’re using one configuration from conf/conf.ts

var lang = {
    availableLangs: {
        en: 'English'
    defaultLang: 'en',
    lang: {
        "true": {
            en: "True",
            es: "Verdadero"
        "false": {
            en: "False",
            es: "Falso"

export {lang};

Now we can translate texts using:

import {Component} from "@angular/core";
import {I18nService} from "../../services/i18n/I18nService";

    templateUrl: 'build/pages/home/home.html'
export class HomePage {
    constructor(private i18n:I18nService) {

    label1:string = this.i18n.translate('true');
    label2:string = 'true';
    ngOnInit() {
        setInterval(() => {
            this.label2 = this.i18n.translate(this.label2 == 'false' ? 'true' : 'false');
        }, 2000);

We also need a Pipe to use i18n within templates

{{ "true" | i18n }}

This is the service:

import {Injectable, Pipe} from "@angular/core";

export class I18nService {

    private conf:any;
    private userLang:string;
    private lang:any;

    setUserLang(lang:string):void {
        this.userLang = lang;

    init(lang:any):void {
        this.conf = lang;

    translate(key:string):string {
        if (typeof this.conf.lang !== 'undefined' && this.conf.lang.hasOwnProperty(key)) {
            return this.conf.lang[key][this.userLang] || key;
        } else {
            return key;

    name: 'i18n',
    pure: false
export class I18nPipe {
    constructor(private i18n:I18nService) {

    transform(key:string) {
        return this.i18n.translate(key);

The code is in my github account. I also have tried to created a npm package and install it using

npm install angular2-i18n --save

I don’t know why it doesn’t work when I use the npm installed package and I works like a charm when I use the code in my project directory

import {I18nService} from "./services/i18n/I18nService"; // works
import {I18nService} from "angular2-i18n/src/I18nService"; // don't work

I also have problems with unit tests. It works when I run the tests locally (it works on my machine ūüôā ) but it doesn’t work when I run them in travis. Any help with those two problems would be appreciated.