Category Archives: Angular

Angular2 Internationalization (i18n)

When you build frontend interfaces for the web, you often have to provide support for different languages, locales and timezones (generally called internationalization or short i18n in computer science). With Angular2 you can use the module “ng2-translate” to provide browser language detection and to resolve internationalized text fragments. In this article I will show how to use language files for Angular2.

Include Angular2 translation module

The ng2-translate  module can be simply added to your project via npm by calling:

Next you have to add the module to your Angular2 application module, by including  TranslateModule  from ng2-translate :

import {NgModule} from ‘@angular/core’; import {HttpModule} from ‘@angular/http’; import {TranslateModule} from ‘ng2-translate’; @NgModule({ imports: [ BrowserModule, HttpModule, TranslateModule.forRoot() ], bootstrap: [AppComponent] }) export class AppModule { }

Provide Language files

By default, the ng2-translate module loads the translated texts in JSON Format from the path "i18n/*.json" , where "*"  is the selected language (de, en, …).

The translation keys are organized in a JSON hierarchy and can be grouped thematically with this feature. So take this example translation file:

There are now the translation keys “ExamplePage.Title”, “ExamplePage.Description”, “AnotherPage.Title”, “AnotherPage.Info” and “AnotherPage.Subsection1.SocialMedia” available.

You need to provide such a file for each language you want to support.

Use in your Angular2 application

In order to enable the translation feature, you first have to initialize the ng2-translation service in your application, e.g. in the initializer of your app component. You can configure which languages you support and which is the default language. You also can use browser detection to get the preferred language of your user agent.

To insert translated texts in your Angular2 template, simply use the “translate” pipe. Put the translation key as input of the pipe, then add “|translate”.

You can also query translations from the TranslationService directly (with the "get"  method), but be aware, that the translation resolution is asynchronous by default (because it could be required to fetch the translation file on the first encounter). Therefore queries of translations always return Observables, unless you force instant evaulation with the "instant"  method (which will fail if the language file is not loaded, yet).

Angular2 RC3 Router

Some days ago, the new Angular2 RC3 release candidate (and also some days earlies RC2) has been released. Again, some changes were made to the Angular2 structure that everyone needs to update in their Angular2 applications to become compatible to the new version. I want to show some of the changes in the new Angular2 RC3 Router in this article.

Angular2 RC3 Router

After the Angular2 Beta Router and the new Router introduced in RC0, yet another Router package has been released and the old one has bee deprecated (and is now still available as package @angular/router-deprecated version 2.0.0-rc.2). According to the team, the new router was necessary to handle some fundamental problems with the previous routing mechanism, which might be working correctly with 90%ish of the use cases, but was not able to handle all use cases Angular2 wants to address.

Although the new router package is official still in Alpha, it has been announced by the Angular2 team, that the new Router package should already be used instead of the old package.

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Angular2 with NPM and Webpack

This article demonstrates how to set up an Angular2 project with Webpack. The setup also supports Typescript, Less, CSS packages like Twitter Bootstrap and Fonts e.g. FontAwesome.

It describes how to set up all the different plugins, loaders etc. I needed for a real Angular2 application. Most articles I read so far only concentrate on one small part of a complete setup. If you think I forgot to mention an elementary part of the setup, please let me know.

Required NPM Packages

All required dependencies for Webpack are put into package.json as devDependencies, so that NPM will automatically install them.

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Angular2 Date Pipe

In Angular2 you can use “pipes” (in earlier versions called “filters”) to adjust data bindings to given situations. Then name comes from the “pipe symbol” (|) that is also known from Unix/Linux command shells to manipulate data streams. In Angular 2, the most common pipes are “date” (date format rendering), “async” (asynchronous data binding of Observables) and String-manipulating pipes like “uppercase” / “lowercase”. I will focus on the “date” pipe in this article.

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Basics of Reactive Events in Angular2

In this article I want to show how to use the “Reactive Events” library RxJS to handle asynchronous event processing in AngularJS2.

In many Javascripts frameworks asynchronous events are handled by either providing a callback function to be called, or be retrieving a “Promise” object to get the data.

The RxJS libraray is taking the concept of promises even further with the interface Observable, which is a combination of a Promise and an Iterator. To be precise, an Observable describes a channel to receive an arbitrary number of events asynchronously over time.

Angular2 adapts this paradigm for all major interactions, as all asynchronous actions can be described by Observables:

  • DOM  Events (e.g. user clicks a button)
  • AJAX Requests
  • Timeouts and Timers

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Angular2 Release Candidate 1 (RC1) Changes

This article summarizes a couple of changes I encountered during the migration of angular2 beta 17 to angular2 rc1.

Angular2 Packages for RC1

Previously angular2 could be pulled in by npm using the following configuration entry in package.json

Now all packages have been split up and moved to @angular instead of angular2.


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Angular2 Http Authentication Interceptor

In my Angular2 application I want to be redirected to the login page whenever I get a 401 response during an Ajax call. Therefore I want to intercept all Ajax calls and check for the response code. In addition to that I also want to set a couple of default request headers for each Ajax call. The code below shows an interceptor for angular2 http requests.

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