Lernen Sie Angular in diesem kostenlosen 33-teiligen Kurs des Angular-Experten Dan Wahlin

Laut der Stack Overflow-Entwicklerumfrage 2018 ist Angular eines der beliebtesten Frameworks / Bibliotheken unter professionellen Entwicklern. Wenn Sie es also lernen, erhöhen sich Ihre Chancen, einen Job als Webentwickler zu bekommen, erheblich.

Aus diesem Grund haben wir uns mit einem der renommiertesten Experten für das Framework zusammengetan und einen kostenlosen Angular-Kurs bei Scrimba erstellt.

Der Kursleiter Dan Wahlin ist ein Google Developer Expert, der Schulungs-, Architektur- und Entwicklungsdienste für einige der größten Unternehmen der Branche bereitgestellt und einige der beliebtesten Schulungskurse zu Udemy und Pluralsight erstellt hat. Er hält außerdem regelmäßig Vorträge bei Entwicklerkonferenzen auf der ganzen Welt.

In diesem Kurs führt Dan Sie durch die Erstellung Ihrer ersten Angular-App mit TypeScript. Wenn Sie den Kurs abschließen, erweitern Sie Ihren Werkzeuggürtel um wertvolle Fähigkeiten.

Schauen wir uns nun an, wie der Kurs aufgebaut ist!

Teil 1: Kursübersicht

Im Einführungsvideo gibt Dan einen Überblick über den Kurs, die wichtigsten Aspekte von Angular und den Aufbau des Kurses. Er erzählt Ihnen auch ein wenig über seinen Hintergrund, damit Sie ihn kennen, bevor Sie in den Code Ihrer neuen App springen.

Teil 2: Anwendungsübersicht

In diesem Teil gibt Dan uns einen Einblick in die App, die wir erstellen werden. Es soll uns ermöglichen, uns auf die wichtigsten Bausteine ​​von Angular zu konzentrieren. Durch die Erstellung einer App zur Anzeige von Kundendaten und deren Bestellungen werden wir uns mit den wichtigsten Aspekten von Angular wie Komponenten, Modulen, Diensten und Routing befassen. Während des Kurses lernen wir außerdem die großartigen Funktionen jeder App kennen, z. B. Sortieren und Filtern.

Teil 3: Angular CLI

In diesem Teil lernen wir die Grundlagen der Verwendung des Angular CLI-Tools (Befehlszeilenschnittstelle) kennen und gehen durch die grundlegenden Befehle:

ng --version ng --help ng new my-app-name ng generate [component | directive | pipe | service | class | interface | enum | guard] ng build ng serve ng lint ng tests 

ng --new my-app-nameErstellen Sie beispielsweise eine neue leere Angular-App für uns, mit der wir ng -generateTeile unserer App erstellen können .

ng buildwird alles für uns erstellen und ng serve -osogar einen Entwicklungsserver starten sowie ein Browserfenster öffnen, in dem wir unsere App anzeigen können.

Teil 4: Übersicht über Projektdateien

In diesem Video des Kurses gibt Dan einen grundlegenden Überblick über die CLI - Befehle für eine leere Eckige app zu erzeugen und gibt einen schnellen Überblick über die Konfigurationsdateien wie tslint, tsconfigund protractorin unseren App - Ordnern.

Teil 5: Das große Ganze

Hier lernen wir eine nützliche Abstraktion, dass Komponenten Lego-Blöcken ähnlich sind - wir bauen Komponenten auf und verwenden sie dann, um eine App zu erstellen. Wir erhalten auch eine kurze Auffrischung der JavaScript-Sprachfamilie und erfahren, wo TypeScripts hineinpasst.

Dan gibt uns ein gutes mentales Modell, mit dem wir bei der Arbeit mit Angular über unseren Code nachdenken können, damit wir uns vorstellen können, wo alles hingehört.

Teil 6: Komponenten und Module - Übersicht

Nicht weg abstrahiert, könnte das Diagramm für Angular-Code so aussehen.

Komponenten bestehen aus Code und HTML-Vorlage und können einen Selektor haben, sodass wir sie in unserem HTML aufrufen können.

Jede Komponente besteht aus:

Dan erklärt dann, was jedes der Teile ist und wie sie in die Angular-Art der Entwicklung von Komponenten passen. Eines der großartigen Dinge an Angular ist, dass es sehr vorhersehbar ist. Sobald Sie gelernt haben, wie Sie Ihre erste Komponente erstellen, sind Sie auf dem besten Weg, zusätzliche Komponenten zu erstellen.

Teil 7: Komponenten und Module - App-Komponente

In diesem Teil des Kurses betrachten wir eine HelloWorldKomponente.

Dan unterteilt jeden Aspekt der Komponente für uns und erklärt, wie sie verwendet wird und wie unsere Komponente von Angular verarbeitet wird, wie sie hinzugefügt wird app.moduleund wie sie letztendlich auf unseren Bildschirmen gerendert wird.

Wir erfahren, dass selector: 'app-root'wir die Komponente später aus unserem HTML-Code verwenden können

Wir haben auch einen kleinen Einblick in die Datenbindung, über die wir in späteren Kapiteln mehr erfahren werden.

Teil 8: Komponenten und Module - App-Modul

In diesem Screencast verbringen wir mehr Zeit damit, etwas über das Innenleben zu app.modulelernen, das wir in der vorherigen Besetzung angesprochen haben, und lernen über NgModuleund BrowserModule.

Teil 9: Komponenten und Module - Hinzufügen einer Kundenkomponente

In dieser Besetzung gibt Dan einige Tipps zum Erstellen von Komponenten mithilfe der CLI und zeigt dann, wie Komponenten manuell erstellt werden. Wir lernen, wie wir eine Komponente strukturieren können, um unser Wissen aus Teil 6 weiter zu erweitern.

Jetzt bringen wir einige Daten ein, um unsere API nachzuahmen, und erfahren, wie Module uns helfen, unseren Code organisiert und einfacher wiederzuverwenden.

Teil 10: Komponenten und Module - Hinzufügen einer Kundenlistenkomponente

In this part, we create a customers-list.component which is an HTML table to display our list of customers. We quickly register in customers.module and use the selector to display our empty table.

Next step would be to populate the table with some data.

Part #11: Components & Modules — Adding a Filter Textbox Component

Before we add some data to our table, Dan shows us how to add a filter-textbox.component to our table and we reinforce the Angular way of creating a component, registering it in a module and using it in our HTML with selectors.

Part #12: Components & Modules — Adding a Shared Module and Interfaces

In this section, Dan talks about using shared.module — a module where we put components or other features that we want to share throughout our app, not just in customers.

We also have a quick refresher on TypeScript interfaces and how they can be used in Angular applications to provide better code help and enhance productivity.

export interface ICustomer { id: number; name: string; city: string; orderTotal?: number; customerSince: any; } 

Part #13: Data Binding — Data Binding Overview

In this chapter we learn about data binding, learn a few techniques and see how to add data binding to our application.

We usually bind data in our templates. Data binding comes into play when a component gets our data and hooks it into a template. We can get data into a template using Property Binding, and handle user events and get data out of a template using Event Binding. Angular provides a robust and clean way to add data binding in templates that’s quick and easy to remember.

Dan provides us with a handy slide to remember syntax required…

…and some on Angular directives, for example, ngFor, used to loop through items in a collection and get some properties from the items, and ngIf to add and remove an HTML element from the DOM.

Part #14: Data Binding — Getting Started with Data Binding

In this cast we play around with Property Binding and Event Binding to better understand how they work in Angular, using the knowledge from the previous chapter.

Dan shows how we can use the [hidden] property to display an h1 element dynamically:

{{ title }}

And to bind DOM events such as click:

Show/Hide 

Part #15: Data Binding — Directives and Interpolation

Here we have a look at Interpolation. The rationale is that we need to get data from each customer to generate a table row in a table from Part #10.

This is the part when things start coming together: we use directive ngFor to loop through each customer in filteredCustomers and interpolate data from a customer into a table row. We learn a few tricks about rendering data conditionally using ngIf.

In the end we get a pretty looking table!

Part #16: Data Binding — Event Binding

Event Binding is crucial when we need to handle an event, like a mouse move or a click. In this screencast, Dan guides us through adding functionality to sort the data in our table. We will start on it in this chapter and finish it when we get to the Services part of our course.

We create a placeholder event handler in our customer-list.component:

sort(prop: string) { // A sorter service will handle the sorting } 

Add binding in customers-list.component.html:

NameCityOrder Total

Part #17: Data Binding — Input Properties

We have some data in a people array in our customers.component and we need to pass it into our filteredCustomers array in customers-list.component, effectively passing data from a parent component to a child.

For that we will use Angular’s Input property which relies on a decorator named Input():

@Input() get customers(): ICustomer[] { return this._customers } set customers(value: ICustomer[]) { if (value) { this.filteredCustomers = this._customers = value; this.calculateOrders(); } } 

And bind to it in our parent component template to pass data from parent to child (app-customers-list in this case):

Part #18: Data Binding — Working with Pipes

Wow! We’ve done quite well so far!

There are a few things which might look a bit odd — “john” is lowercase and we have no “$” symbol to display currency in which we have our orders.

This is really the way we have our data, so we could just go and update it directly, or we can use a built-in Angular feature called Pipes to update it for us!

Some of the simplest pipes look like this:

{ uppercase } // renders JOHN { cust.name } // renders John 

But sometimes you might want to have your own custom pipe and Dan shows us how to build a custom capitalize pipe (note that Angular includes one called titlecase — but we’re learning here!) and how to wire it up to use in our application.

Part #19: Data Binding — Adding Filtering

In this cast, Dan walks us through adding functionality to our filter-textbox.component from Part #11

We learn more about Angular Output and EventEmitter properties, create our filter event handler and bind it to our filter textbox:

And there we go, we can now filter on our customers’ names!

Part #20: Services and Http — Services Overview

In this chapter, we look at Angular Services. One of Angular’s strong points is that it’s a complete framework that provides built-in support for managing state and objects through services. We saw services in the diagram earlier. Since we don’t want components to know how to do too much, we’ll rely on services to communicate with the server, perform client-side validation or calculations, etc.

Components should focus on presenting data and handling user events. When additional functionality needs to be performed they should delegate to services to provide for a more maintainable application and better code reuse.

That’s exactly what Service does — some reusable functionality for the app which should not be of any component’s concern.

Luckily, Dan get us covered with a handy slide to keep in mind.

Part #21: Services and Http — Creating and Providing a Service

From a chapter earlier we have seen an import of Injectible which is a decorator that allows for something called Dependency Injection or DI for short (another powerful feature built-into Angular).

We’ll use DI to access an HttpClient service which we will use to communicate with a RESTful service. We will be adding HttpClient to a constructor of our data.service and @Injectible() decorator will make DI possible.

Part #22: Services and Http — Calling the Server with HttpClient

In this cast, Dan introduces Observables from RxJS — reactive extensions for JavaScript, which is not a part of Angular but is included in all Angular projects by default.

We will be using Observables to deal with asynchronous code. In a nutshell, it allows us to start an operation and then subscribe to data that is returned. Once the data comes back from the server, the subscription ends and we can unsubscribe.

Dan discusses the necessary code to call the server and then subscribe to the response using RxJS piping and operators.

Here’s an example of how we can get Orders:

Part #23: Services and Http — Injecting a Service into a Component

Now that we have a way to get the data, we need to inject the service into one of our components. We can now change this.people in customers.component from being hardcoded to call a service and get data that way.

We need to bring our data.service to app.module and then in customers.component we can:

import { DataService } from '../core/data.service'; 

Now we can inject our DataService straight into our component’s constructor:

constructor(private dataService: DataService) {} 

Part #24: Services and Http — Subscribing to an Observable

Now we can use our injected dataService, call getCustomers() and subscribe to our Observable to get the data.

Which is pretty straightforward:

ngOnInit() { this.title = 'Customers'; this.dataService.getCustomers() .subscribe((customers: ICustomer[]) => this.people = customers); 

Now we have one last service to look at — SorterService

Part #25: Services and Http — Using a SorterService

Currently, if we click on our column headers nothing would happen.

Dan handily provided a prewritten service for us, which we can use, so in this chapter, we will practice bringing in service into our components, in this case, customers-list.component.

As with other services we need to import it:

import { SorterService } from '../../core/sorter.service'; 

Then we inject SorterService into our constructor:

constructor(private sorterService: SorterService) {} 

Dependency injection makes it extremely easy to access reusable code such as the sorter or data services.

Lastly, we use it in our sort() function:

sort(prop: string) { this.sorterService.sort(this.filteredCustomers, prop); } 

Part #26: Routing — Routing Overview

This chapter will introduce Routing, which is an essential part of modern applications. As you’re building an Angular app, you want to show different components as the user interacts with it. In our case, when a user clicks on a Customer, we might want to show them Orders. Routing is one way to very neatly achieve this.

Routes are used to hook a specific URL to a component and in the next few chapters, we will be focusing on the top part of our Angular diagram.

A super great part of routing is that if a user bookmarks a specific URL, it will bring them back to a specific component and there is no need for complex show/hide logic.

Part #27: Routing — Creating a Routing Module with Routes

We begin with a familiar module-container routine and create a app-routing.module.

A main focus of the app-routing.module is to define the routes in an array:

const routes: Routes = [ { path: '', pathMatch: 'full', redirectTo: '/customers'}, { path: '**', redirectTo: '/customers' } ]; 

Three key properties of routes are:

  • path — where your user goes, so path: '' would be the root of your app. path: '**' is a wild card match. It is usually placed last and it’s there to cover cases for any route that is not specified in routes
  • pathMatch — how exactly should the route match for a specific component to be displayed
  • redirectTo — when a path is matched, this is where we send the user. In our case, we send them to /customers.

Part #28: Routing — Using Router Outlet

In order to use Routing in Angular in our app.component template we replace with . Ultimately, this is just a way to say: ‘Hey, this is where a component will go when we hit our route’.

When we hit a route, then a component associated with that route will magically appear in the place of .

Part #29: Routing — Adding a Customers Routing Module and Routes

In this chapter, Dan brings all the things together and we connect a /customer route to customers.component.

First, we create acustomers-routing.module and point our route from part #28 to customers.component like so:

const routes: Routes = [ { path: 'customers', component: CustomersComponent } ]; 

And now when we type “customers” in the Scrimba browser address bar we get our customers.component.

Part #30: Routing — Adding an Orders Component with Routes

In this clip, we’re going to quickly review how we’ve done routing to display customers, and now it’s time for routing to display their orders.

There’s a little catch though. When we click on a customer we need to display order data related to that customer. So we need to pass some dynamic data into our routing.

We can achieve this by passing a route parameter in our orders-routing.module like so:

const routes: Routes = [ { path: 'orders/:id', component: OrdersComponent} ]; 

Note the /:id syntax. In routing the : symbol indicates that the value after it will be dynamically replaced and id is just a variable, so it can be anything like :country or :book.

Part #31: Routing — Accessing Route Parameters

In the previous screencast we saw how to create orders/:id route and now orders.component needs to somehow grab that id and display customer related orders. To do that we need to access the id route parameter.

One way of doing it would be:

let id = this.route.paramMap.get('id'); 

The benefit of this way is that we can subscribe to paramMap and get notified when any of the data in id changes. But we only need it once.

We can use snapshot for that:

let id = this.route.snapshot.paramMap.get('id') 

snapshot just takes a kind of an instant picture of your URL and gives it to you, which perfect as that’s what we need in this situation.

But now we have a problem. Our id is a string, but to get an order from our DataService it needs to be a number. We can convert it with parseInt(), but Dan teaches us a neat + trick:

let id = +this.route.snapshot.paramMap.get('id') 

Now we can call DataService to get the order and render it to orders.component.

Part #32: Routing — Linking to Routes with the routerLink Directive

The last thing we want to do is to add a link on a customer’s name, so we can click it to see their orders.

In part #28 we’ve added and now we just need to tell our app that we want to display orders.component when we navigate to /orders/:id.

We can do it by adding a link to our customer’s name in customers-list.component.html in a row where we’re mapping all the data to be displayed. We already have our customer object there, so we can just pass id to our route.

 { capitalize }  

Now we can see orders!

Original text


But hey, how do we get back? We could click ‘Back’ button on the browser, but it’s much nicer to have an app link for that, now that we know routing. Let’s add it to customers-list.component.html at the very bottom.

View All Customers 

Part #33: Course Summary

Very well done, we have our app now!

We can wrap up and have a quick recap of things done. Don’t forget to watch the actual screencast of the course, as Dan is a great teacher so you will have lots of fun following the process alongside him!

Thank you, Dan!

If you’re interested in keeping up on front-end and back-end technologies make sure to follow Dan on Twitter!

Happy coding!

Thanks for reading! My name is Per Borgen, I'm the co-founder of Scrimba – the easiest way to learn to code. You should check out our responsive web design bootcamp if want to learn to build modern website on a professional level.