Lær vinklet i dette gratis 33-delt kursus af Angular-ekspert Dan Wahlin

Ifølge Stack Overflow-udviklerundersøgelsen 2018 er Angular en af ​​de mest populære rammer / biblioteker blandt professionelle udviklere. Så at lære det øger dine chancer for at få et job som webudvikler betydeligt.

Derfor har vi gået sammen med en af ​​de mest kendte eksperter inden for rammerne og skabt et gratis Angular-kursus på Scrimba.

Instruktør Dan Wahlin er en Google-udviklerekspert, der har leveret uddannelses-, arkitektur- og udviklingstjenester til nogle af de største virksomheder i branchen og skabt nogle af de mest populære kurser i Udemy og Pluralsight. Han er også en regelmæssig højttaler på udviklerkonferencer rundt om i verden.

På dette kursus guider Dan dig gennem oprettelse af din allerførste Angular-app ved hjælp af TypeScript. Ved at gennemføre kurset tilføjer du værdifulde færdigheder til din værktøjsbælte.

Lad os nu se på, hvordan kurset er struktureret!

Del # 1: Kursusoversigt

I introduktionsvideoen giver Dan et overblik over kurset, centrale aspekter af Angular, og hvordan kurset er lagt ud. Han fortæller dig også lidt om sin baggrund, så du er fortrolig med ham, inden du hopper ind i koden til din nye app.

Del # 2: Applikationsoversigt

I denne del giver Dan os et indblik i den app, vi skal bygge. Det er designet til at give os mulighed for at fokusere på de vigtigste byggesten i Angular. Ved at oprette en app til at vise kundedata og deres ordrer vil vi finpudse nøgleaspekterne i Angular, såsom komponenter, moduler, tjenester og routing. I løbet af kurset vil vi også lære om fantastiske funktioner, som hver app har, som sortering og filtrering.

Del # 3: Vinkel CLI

I denne del lærer vi det grundlæggende ved brug af værktøjet Angular CLI (kommandolinjegrænseflade) og går gennem de grundlæggende kommandoer:

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 

For eksempel ng --new my-app-nameopretter en ny tom kantet app til os, og vi kan bruge ng -generatetil at oprette dele af vores app.

ng buildvil bygge alt for os og ng serve -ovil endda starte en udviklingsserver samt åbne et browservindue, som vi kan se vores app i.

Del # 4: Oversigt over projektfiler

I denne video af kurset, Dan giver et grundlæggende overblik over CLI kommando til at generere en tom Kantet app og giver et hurtigt overblik over de konfigurationsfiler som tslint, tsconfigog protractori vores app mappe.

Del # 5: Det store billede

Her lærer vi en nyttig abstraktion om, at komponenter ligner Lego-blokke - vi opbygger komponenter og bruger dem derefter til at holde sammen for at lave en app. Vi får også en hurtig opdatering af JavaScript-sprogfamilien og lærer, hvor TypeScripts passer ind.

Dan giver os en god mental model til at tænke på vores kode, mens vi arbejder med Angular, så vi kan forestille os, hvor det hele passer ind.

Del # 6: Komponenter og moduler - Oversigt

Ikke abstraheret væk, kan diagrammet for kantet kode se sådan ud.

Komponenter består af kode og HTML-skabelon, og det kan have en vælger, så vi kan kalde det i vores HTML.

Hver komponent består af:

Dan forklarer derefter, hvad hver af delene er, og hvordan de passer ind i den vinkelformede måde at udvikle komponenter på. En af de store ting ved Angular er, at den er meget forudsigelig. Når du først har lært, hvordan du opretter din første komponent, er du godt på vej til at oprette yderligere komponenter.

Del # 7: Komponenter og moduler - Appkomponent

I denne del af kurset ser vi på en HelloWorldkomponent.

Dan nedbryder alle aspekter af komponenten for os og forklarer, hvordan den bruges, og hvordan vores komponent behandles af Angular, hvordan den føjes til app.moduleog i sidste ende, hvordan den gengives på vores skærme.

Vi lærer, at det selector: 'app-root'er det, der giver os mulighed for senere at kalde komponenten fra vores HTML ved hjælp af

Vi har også et smugkig på databinding, som vi lærer mere om i senere kapitler.

Del # 8: Komponenter og moduler - App-modul

I denne screencast bruger vi mere tid på at lære om de indre funktioner, app.modulesom vi berørte i den forrige rollebesætning, og lære om NgModuleog BrowserModule.

Del # 9: Komponenter og moduler - Tilføjelse af en kundekomponent

I denne rollebesætning giver Dan os nogle tip til oprettelse af komponenter ved hjælp af CLI og viser derefter, hvordan man opretter komponenter manuelt. Vi lærer at strukturere en komponent, der yderligere udvider vores viden fra del 6.

Nu bringer vi nogle data ind for at efterligne vores API og lærer om, hvordan moduler hjælper os med at holde vores kode organiseret og lettere at genbruge.

Del # 10: Komponenter og moduler - Tilføjelse af en kundelistekomponent

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!

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.