TL;DR: In this article, I'll cover the new features in Angular 6 and several other changes and deprecations.


Angular is a very popular framework that is actively maintained by Google. Its popularity and wide adoption have been driven by how it keeps evolving and getting better by the day. Angular powers a lot of web platforms such as Google Adwords, Google Fiber, Adsense, and Winc.

The previous major Angular version was Angular 5. We covered the major features and bug fixes that shipped with Angular 5 before. Now, we are going to cover the latest major release, Angular 6, which focuses on making Angular smaller and faster to use.

Let's go through the major changes in Angular 6.

1. Improved Service Worker Support

Angular 6 now supports the configuration of navigation URLs in Service Workers. The service worker will redirect navigation requests that don't match any asset or data group to the specified index file.

"Angular 6 now supports configuration of navigation URLs in Service Workers."

By default, a navigation request can have any URL except for those containing __ and URLs containing a file extension (i.e a .) in the last path segment. Sometimes it is great to be able to configure different rules for the URLs of navigation requests (e.g. ignore specific URLs and pass them through to the server).

Now, you can specify an optional navigationUrls list in ngsw-config.json. which contains URLs or simple globs. Only requests whose URLs match any of the positive URLs/patterns and none of the negative ones (i.e. URLs/patterns starting with !) will be considered navigation requests and handled the right way by the service worker.

Before now, the service worker would enter a degrade mode where only existing clients would be served if either the client or server was offline while trying to fetch ngsw.json. In Angular 6, the service worker remains in the current mode until connectivity to the server is restored.

Furthermore, a helper script, safety-worker.js, has been added to the service worker package to enable easy deactivation of an existing service worker in production.

packages/service-worker/safety-worker.js

self.addEventListener('install', event => { self.skipWaiting(); });

self.addEventListener('activate', event => {
  event.waitUntil(self.clients.claim());
  self.registration.unregister().then(
      () => { console.log('NGSW Safety Worker - unregistered old service worker'); });
});

2. Goodbye Template Element

The <template> element was deprecated long ago, precisely in Angular 4. It has been removed completely in Angular 6.

The <ng-template> element should be used instead.

Before:

<template>some template content</template>

Now:

<ng-template>some template content</ng-template>

3. Better URL Serialization

Before now, there were issues around routes and URL serialization such as this below:

What's new in Angular 6 - URL Serialization What's new in Angular 6 - URL Serialization

In Angular 6, issues like the one above have been fixed and:

  • URI fragments will now serialize the same as query strings.
  • In the URL path, (portion prior to the query string and/or fragment), the plus sign (+) and ampersand (&) will appear decoded.
  • In the URL path, parentheses values (( and )) will now appear percent-encoded as %28 and %29 respectively.
  • In the URL path, semicolons will be encoded in their percent encoding %3B.

It's also important to know that parentheses and semicolons denoting auxiliary routes will, in any case, show up in their decoded shape except for parentheses and semicolons used as values in a segment or key/value pair for matrix params which will show up encoded.

4. Support Added for Custom Elements

This is crazy. When I discovered this, I jumped! Let me explain before you get too excited.

The support is currently experimental and unstable. It's targeted to land and become stable in the Angular 6.x release cycle.

With this support, developers can simply register Angular Components as Custom Elements. Once registered, these components can be used just like built-in HTML elements. They are HTML Elements, so why not?

So, Angular developers can do something like this:

//my-name.ts

import { Component, Input, NgModule } from '@angular/core';
import { createCustomElement } from '@angular/elements';

@Component({
  selector: 'my-name',
  template: `<h1>Hello my name is {{name}}</h1>`
})

export class MyName {
  @Input() name: string = 'Prosper!';
}

@NgModule({
  declarations: [ MyName ],
  entryComponents: [ MyName ]
})

export class MyNameModule {}
//app.component.ts
import { Component, NgModuleRef } from '@angular/core';
import { createCustomElement } from '@angular/elements';

import { MyName } from './my-name.ngfactory';

@Component({
  selector: 'app-root',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.css']
})

export class AppComponent {
  constructor(private injector: Injector, ngModuleRef: NgModuleRef) {
    const ngElementConfig = createCustomElement(MyName, injector);
    customElements.define('my-name', NgElementConfig);
  }
}

5. Forms Validation in Angular 6

Before now, ngModelChange was always emitted before the underlying form control was updated.

If you had a handler for the ngModelChange event that checked the value through the control, the old value would be logged instead of the updated value. This is not the case if you pass the value through the $event keyword directly.

Check out this example:

Passing the value through the $event keyword directly

<input [(ngModel)]="name" (ngModelChange)="onChange($event)">
onChange(value) {
   console.log(value); // logs updated value
}

Using a Handler

<input #modelDir="ngModel" [(ngModel)]="name" (ngModelChange)="onChange(modelDir)">
onChange(ngModel: ngModel) {
   console.log(ngModel.value); // logs old value
}

In Angular 6, ngModelChange is now emitted after the value is updated on its form control.

"In Angular 6, ngModelChange is now emitted after the value is updated on its form control."

onChange(ngModel: NgModel) {
   console.log(ngModel.value); // logs updated value
}

6. Multiple Validators for Form Builder Array

In previous versions of Angular, you could set only one validator on a FormArray field with the FormBuilder.array method.

In Angular 6, you can set multiple validators with the FormBuilder.array method:

...
ngOnInit() {
  this.speakerForm = this.formBuilder.group({
    text: ['', Validators.required],
    options: this.formBuilder.array([], [MyValidators.correctProposalCount, MyValidators.totalProposals])
  });
}

7. Token Marking for Runtime Animation Context

In Angular 6, it's now possible to determine which animation context is used for a component at runtime. A token is provided as a marker to determine whether the component is running a BrowserAnimationsModule or NoopAnimationsModule context at runtime.

8. Hello Schematics

Schematics is a new scaffolding library that's used by the Angular CLI to generate custom templates. The Angular team has always been keen on improving developer productivity, which explains the birth of schematics.

With Schematics, you can easily create Angular libraries like so:

First, install the necessary schematic tools:

npm i -g  ng-lib-schematics  @angular-devkit/core @angular-devkit/schematics-cli

Next, create a new angular-cli project:

ng new avengers --skip-install // avengers is the name of the new library I'm trying to create

Finally, you can just run schematics like so:

schematics ng-lib-schematics:lib-standalone --name avengers

A new lib directory will be generated for you inside the src folder. The lib directory ships with a sample demo and the build tools necessary for a typical Angular package.

Check out this deep and excellent guide to Schematics.

Deprecations and Other Updates

  • Angular 6 ships with Rxjs 6.0.0.
  • @Injectable now supports tree-shakeable tokens.
  • Service workers now properly handle invalid hashes in all scenarios.
  • The router sometimes hits a race condition while a route is being instantiated and a new navigation request arrives. This issue has been solved in Angular 6.
  • Avoid overriding ngInjectableDef in the decorator if present on the type.

Check out other Angular 6 updates here.

Upgrading to Angular 6

The Angular team built an awesome tool to make upgrading as easy as possible.

Angular 6 Upgrade Angular 6 upgrade tool

Aside: Authenticate an Angular App and Node API with Auth0

We can protect our applications and APIs so that only authenticated users can access them. Let's explore how to do this with an Angular application and a Node API using Auth0. You can clone this sample app and API from the angular-auth0-aside repo on GitHub.

Auth0 login screen

Features

The sample Angular application and API has the following features:

  • Angular application generated with Angular CLI and served at http://localhost:4200
  • Authentication with auth0.js using a login page
  • Node server protected API route http://localhost:3001/api/dragons returns JSON data for authenticated GET requests
  • Angular app fetches data from API once user is authenticated with Auth0
  • Profile page requires authentication for access using route guards
  • Authentication service uses subjects to provide authentication and profile data to the app

Sign Up for Auth0

You'll need an Auth0 account to manage authentication. You can sign up for a free account here. Next, set up an Auth0 application and API so Auth0 can interface with an Angular app and Node API.

Set Up an Auth0 Application

  1. Go to your Auth0 Dashboard: Applications section and click the "+ Create Application" button.
  2. Name your new app and select "Single Page Web Applications".
  3. In the Settings for your new Auth0 app, add http://localhost:4200/callback to the Allowed Callback URLs.
  4. Add http://localhost:4200 to both the Allowed Web Origins and Allowed Logout URLs. Click the "Save Changes" button.
  5. If you'd like, you can set up some social connections. You can then enable them for your app in the Application options under the Connections tab. The example shown in the screenshot above uses username/password database, Facebook, Google, and Twitter.

Note: Set up your own social keys and do not leave social connections set to use Auth0 dev keys or you will encounter issues with token renewal.

Set Up an API

  1. Go to APIs in your Auth0 dashboard and click on the "Create API" button. Enter a name for the API. Set the Identifier to your API endpoint URL. In this example, this is http://localhost:3001/api/. The Signing Algorithm should be RS256.
  2. You can consult the Node.js example under the Quick Start tab in your new API's settings. We'll implement our Node API in this fashion, using Express, express-jwt, and jwks-rsa.

We're now ready to implement Auth0 authentication on both our Angular client and Node backend API.

Dependencies and Setup

The Angular app utilizes the Angular CLI. Make sure you have the CLI installed globally:

$ npm install -g @angular/cli

Once you've cloned the project on GitHub, install the Node dependencies for both the Angular app and the Node server by running the following commands in the root of your project folder:

$ npm install
$ cd server
$ npm install

The Node API is located in the /server folder at the root of our sample application.

Find the config.js.example file and remove the .example extension from the filename. Then open the file:

// server/config.js (formerly config.js.example)
module.exports = {
  CLIENT_DOMAIN: '[YOUR_AUTH0_DOMAIN]', // e.g., 'you.auth0.com'
  AUTH0_AUDIENCE: 'http://localhost:3001/api/'
};

Change the CLIENT_DOMAIN value to your full Auth0 domain and set the AUTH0_AUDIENCE to your audience (in this example, this is http://localhost:3001/api/). The /api/dragons route will be protected with express-jwt and jwks-rsa.

Note: To learn more about RS256 and JSON Web Key Set, read Navigating RS256 and JWKS.

Our API is now protected, so let's make sure that our Angular application can also interface with Auth0. To do this, we'll activate the src/environments/environment.ts.example file by deleting .example from the file extension. Then open the file and change the [YOUR_CLIENT_ID] and [YOUR_AUTH0_DOMAIN] strings to your Auth0 information:

// src/environments/environment.ts (formerly environment.ts.example)
...
export const environment = {
  production: false,
  auth: {
    CLIENT_ID: '[YOUR_CLIENT_ID]',
    CLIENT_DOMAIN: '[YOUR_AUTH0_DOMAIN]', // e.g., 'you.auth0.com'
    ...
  }
};

Our app and API are now set up. They can be served by running ng serve from the root folder and node server from the /server folder. The npm start command will run both at the same time for you by using concurrently.

With the Node API and Angular app running, let's take a look at how authentication is implemented.

Authentication Service

Authentication logic on the front end is handled with an AuthService authentication service: src/app/auth/auth.service.ts file. We'll step through this code below.

// src/app/auth/auth.service.ts
import { Injectable } from '@angular/core';
import { BehaviorSubject, Observable, bindNodeCallback, of } from 'rxjs';
import * as auth0 from 'auth0-js';
import { environment } from './../../environments/environment';
import { Router } from '@angular/router';

@Injectable()
export class AuthService {
  // Create Auth0 web auth instance
  // @TODO: Update environment variables and remove .example
  // extension in src/environments/environment.ts.example
  private _Auth0 = new auth0.WebAuth({
    clientID: environment.auth.CLIENT_ID,
    domain: environment.auth.CLIENT_DOMAIN,
    responseType: 'id_token token',
    redirectUri: environment.auth.REDIRECT,
    audience: environment.auth.AUDIENCE,
    scope: 'openid profile email'
  });
  // Track whether or not to renew token
  private _authFlag = 'isLoggedIn';
  // Create stream for token
  token$: Observable<string>;
  // Create stream for user profile data
  userProfile$ = new BehaviorSubject<any>(null);
  // Authentication navigation
  onAuthSuccessUrl = '/';
  onAuthFailureUrl = '/';
  logoutUrl = environment.auth.LOGOUT_URL;
  // Create observable of Auth0 parseHash method to gather auth results
  parseHash$ = bindNodeCallback(this._Auth0.parseHash.bind(this._Auth0));
  // Create observable of Auth0 checkSession method to
  // verify authorization server session and renew tokens
  checkSession$ = bindNodeCallback(this._Auth0.checkSession.bind(this._Auth0));

  constructor(private router: Router) { }

  login() {
    this._Auth0.authorize();
  }

  handleLoginCallback() {
    if (window.location.hash && !this.authenticated) {
      this.parseHash$().subscribe(
        authResult => {
          this._setAuth(authResult);
          window.location.hash = '';
          this.router.navigate([this.onAuthSuccessUrl]);
        },
        err => this._handleError(err)
      )
    }
  }

  private _setAuth(authResult) {
    // Observable of token
    this.token$ = of(authResult.accessToken);
    // Emit value for user data subject
    this.userProfile$.next(authResult.idTokenPayload);
    // Set flag in local storage stating this app is logged in
    localStorage.setItem(this._authFlag, JSON.stringify(true));
  }

  get authenticated(): boolean {
    return JSON.parse(localStorage.getItem(this._authFlag));
  }

  renewAuth() {
    if (this.authenticated) {
      this.checkSession$({}).subscribe(
        authResult => this._setAuth(authResult),
        err => {
          localStorage.removeItem(this._authFlag);
          this.router.navigate([this.onAuthFailureUrl]);
        }
      );
    }
  }

  logout() {
    // Set authentication status flag in local storage to false
    localStorage.setItem(this._authFlag, JSON.stringify(false));
    // This does a refresh and redirects back to homepage
    // Make sure you have the logout URL in your Auth0
    // Dashboard Application settings in Allowed Logout URLs
    this._Auth0.logout({
      returnTo: this.logoutUrl,
      clientID: environment.auth.CLIENT_ID
    });
  }

  private _handleError(err) {
    if (err.error_description) {
      console.error(`Error: ${err.error_description}`);
    } else {
      console.error(`Error: ${JSON.stringify(err)}`);
    }
  }

}

This service uses the auth config variables from environment.ts to instantiate an auth0.js WebAuth instance. Next an _authFlag member is created, which is simply a flag that we can store in local storage. It tells us whether or not to attempt to renew tokens with the Auth0 authorization server (for example, after a full-page refresh or when returning to the app later). All it does is state, "This front-end application thinks this user is authenticated" and then allows us to apply logic based on that estimation and verify whether or not it's accurate.

We'll add and type a token$ observable, which will provide a stream of the access token string. This is for use with the token interceptor. We don't want our interceptor to utilize a stream that emits a default value without any useable values. We'll declare token$ in our _setAuth() method below, when the access token becomes available.

We will use an RxJS BehaviorSubject to provide a stream of the user profile that you can subscribe to anywhere in the app. We'll also store some paths for navigation so the app can easily determine where to send users when authentication succeeds, fails, or the user has logged out.

The next thing that we'll do is create observables of the auth0.js methods parseHash() (which allows us to extract authentication data from the hash upon login) and checkSession() (which allows us to acquire new tokens when a user has an existing session with the authorization server). Using observables with these methods allows us to easily publish authentication events and subscribe to them within our Angular application.

We'll create observables of the callbacks from these two auth0.js methods using using RxJS's bindNodeCallback. In order to preserve the scope of this, we'll bind() it like so:

bindNodeCallback(this._Auth0.parseHash.bind(this._Auth0))

The login() method authorizes the authentication request with Auth0 using the environment config variables. A login page will be shown to the user and they can then authenticate.

Note: If it's the user's first visit to our app and our callback is on localhost, they'll also be presented with a consent screen where they can grant access to our API. A first party client on a non-localhost domain would be highly trusted, so the consent dialog would not be presented in this case. You can modify this by editing your Auth0 Dashboard API Settings. Look for the "Allow Skipping User Consent" toggle.

We'll receive accessToken, expiresIn, and idTokenPayload in the URL hash from Auth0 when returning to our app after authenticating at the login page. The handleLoginCallback() method subscribes to the parseHash$() observable to stream authentication data (_setAuth()) by creating our token$ observable and emitting a value for the userProfile$ behavior subject. This way, any subscribed components in the app are informed that the token and user data has been updated. The _authFlag is also set to true and stored in local storage so if the user returns to the app later, we can check whether to ask the authorization server for a fresh token. Essentially, the flag serves to tell the authorization server, "This app thinks this user is authenticated. If they are, give me their data." We check the status of the flag in local storage with the accessor method authenticated.

Note: The user profile data takes the shape defined by OpenID standard claims.

The renewAuth() method, if the _authFlag is true, subscribes to the checkSession$() observable to ask the authorization server if the user is indeed authorized (we can pass arguments to this observable as we would to the auth0.js function). If they are, fresh authentication data is returned and we'll run the _setAuth() method to update the necessary authentication streams in our app. If the user is not authorized with Auth0, the _authFlag is removed and the user will be redirected to the URL we set as the authentication failure location.

Next, we have a logout() method that sets the _authFlag to false and logs out of the authentication session on Auth0's server. The Auth0 logout() method then redirects back to the location we set as our logoutUrl.

Once AuthService is provided in app.module.ts, its methods and properties can be used anywhere in our app, such as the home component.

Callback Component

The callback component is where the app is redirected after authentication. This component simply shows a loading message until the login process is completed. It executes the authentication service's handleLoginCallback() method to parse the hash and extract authentication information.

// src/app/callback/callback.component.ts
import { Component, OnInit } from '@angular/core';
import { AuthService } from '../auth/auth.service';

@Component({
  selector: 'app-callback',
  template: `<div>Loading...</div>`,
  styles: []
})
export class CallbackComponent implements OnInit {
  constructor(private auth: AuthService) { }

  ngOnInit() {
    this.auth.handleLoginCallback();
  }

}

Making Authenticated API Requests

In order to make authenticated HTTP requests, it's necessary to add an Authorization header with the access token to our outgoing requests. Note that the api.service.ts file does not do this.

Instead, this functionality is in an HTTP interceptor service called token.interceptor.ts.

// src/app/auth/token.interceptor.ts
import { Injectable } from '@angular/core';
import { HttpRequest, HttpHandler, HttpEvent, HttpInterceptor } from '@angular/common/http';
import { AuthService } from './auth.service';
import { Observable } from 'rxjs';
import { mergeMap } from 'rxjs/operators';

@Injectable()
export class InterceptorService implements HttpInterceptor {
  constructor(private auth: AuthService) { }

  intercept(
    req: HttpRequest<any>,
    next: HttpHandler
  ): Observable<HttpEvent<any>> {
    // @NOTE: If you have some endpoints that are public
    // and do not need Authorization header, implement logic
    // here to accommodate that and conditionally let public
    // requests pass through based on your requirements
    return this.auth.token$
      .pipe(
        mergeMap(token => {
          if (token) {
            const tokenReq = req.clone({
              setHeaders: { Authorization: `Bearer ${token}` }
            });
            return next.handle(tokenReq);
          }
        })
      );
  }
}

As mentioned above, we can return the token$ observable to acquire a token, then clone the outgoing HTTP request and attach an Authorization header before sending the request on its way.

The interceptor should be provided like so in the app-routing.module.ts file:

// src/app/app-routing.module.ts
...
import { HTTP_INTERCEPTORS } from '@angular/common/http';
import { InterceptorService } from './auth/token.interceptor';
...

@NgModule({
  imports: [...],
  providers: [
    ...,
    {
      provide: HTTP_INTERCEPTORS,
      useClass: InterceptorService,
      multi: true
    }
  ],
  ...
})
export class AppRoutingModule {}

Note: We set multi to true because we could implement multiple interceptors, which would run in the order of declaration.

Final Touches: Route Guard and Profile Page

A profile page component can show an authenticated user's profile information. However, we only want this component to be accessible if the user is logged in.

With an authenticated API request and login/logout implemented in the Home component, the final touch is to protect our profile route from unauthorized access. The auth.guard.ts route guard can check authentication and activate routes conditionally. The guard is implemented on specific routes of our choosing in the app-routing.module.ts file like so:

// src/app/app-routing.module.ts
...
import { AuthGuard } from './auth/auth.guard';
...

@NgModule({
  imports: [
    RouterModule.forRoot([
      ...,
      {
        path: 'profile',
        component: ProfileComponent,
        canActivate: [
          AuthGuard
        ]
      },
      ...
    ])
  ],
  providers: [
    AuthGuard,
    ...
  ],
  ...
})
export class AppRoutingModule {}

To Do: Elegant Error Handling

Now that the primary functionality is there, you'll want to think about gracefully handling and reacting to errors. Some functionality will need to be implemented for this. The errors are there to react to, but you'll want to consider how you prefer to respond to them when they occur.

More Resources

That's it! We have an authenticated Node API and Angular application with login, logout, profile information, and a protected route. To learn more, check out the following resources:

Conclusion

Angular 6 came loaded with new features and significant improvements. Kudos to the Angular team on making Angular faster and better to use.

Have you upgraded to Angular 6 yet? What are your thoughts? Did you notice any significant improvement? Let me know in the comments section! 😊