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You can change it to the prefix of your preference by editing the prefix property in.
So, we have a constructor for our component as well as an ngOnInit function for it. But on a basic level, think about these methods like this: A constructor is being called right after the creation of the component, long before data to be passed to it is ready and populated, while ngOnInit only runs after the first cycle of changes to the data, so you have access to your component inputs.
But AppComponent will be loaded before anything else in the app, so we have to consider it to be tidy and small. Angular CLI tells us that it updated app. We can read more about both of them in the documentation.
AppComponent was here before we started to generate any code, so our new components actually populated the module in two places: First, they are imported from their definition files, and then, they are included in the declarations array of our NgModule decorator.
If 'app-card-list' is an Angular component, then verify that it is part of this module. For that, we need to create our first input. Now, we have our card array in our CardList. How can we display it instead of our current markup?
What does it mean? Structural directives control the structure of our template. So ngFor a repeater directive and it will repeat our app card for every element in the array of cards. As soon as we do that, we get this: Of course, we want to display the actual contents of our card array, and for that, we need to pass the card object to the card component as well. Angular is telling us that we still need to define our input in the Card component.
Or, you might have seen it in all those fancy AngularJS demos, where you input value to input and it updates the page content for us. Actually, Angular gives us a little syntax sugar for it, which we can use here, so I started from a different angle to explain how this sugar works.
So we can just write simpler code that takes our value and binds it to both the value of the input and our variable in code. Unfortunately, after we added ngModel, we are getting the error, Can't bind to 'ngModel' since it isn't a known property of 'input'..
We need to import ngModel to our AppModule. But from where?
So we need to edit out AppModule thusly: [ For communicating data to the component Angular, we must have input. To send data from the component, we should use its payload. So we need to subscribe to the events—how do we do that? Now we need to implement the addCard method on our AppComponent.
We need to listen for the DOM keypress event in our component and output the Angular event triggered by that. Working with Forms There are a couple of approaches to working with forms in Angular—one is template-driven and we are already using the most valuable part of it: ngModel for two-way binding.
But forms in Angular are not only about model values, but also about validity. The hash form is a template reference variable that we can use to access our form out of our code.
Using that, we can access any element marked by template reference value—in this case, our form, and we actually declare it as our Component public variable form, so we can write this.
Working with template driven forms is absolutely the same as we did before with simple HTML forms. If we need something more complex, there is a different kind of form for that case in Angular: reactive. First of all, we are using dependency injection for FormBuilder on our constructor and building our form with it. The text there is a name of our field, an empty string is the initial value, and Validators.
We use. By using formControlName, we are telling Angular what field in the reactive form we should use. For now, the main difference between the previous approach with template-driven forms and the new approach with reactive forms is in more coding on the reactive side. It absolutely is.
We are seeing RxJS in action. I guess you all know at least something about promises and building asynchronous code. Promise handling a single event. We ask the browser to make POST, for example, and it returns us a promise. RxJS operates with Observables, which handle streams of events.
Think about that like this: We have just implemented code that is called on every change of our form. If we process user changes with promises, only the first user change will be processed before we need to resubscribe. What is takeWhile here? We are subscribing to our Observables in our components.
Do we need to do all of that boilerplate code? Actually, we can cheat and use the takeWhile operator. By using it, we make sure that our stream will stop emitting new values as soon as this. To do that, create proxy. For that to work, we need to add one more thing to our app configuration; in package. How can we work with the API from Angular?
Angular gives us HttpClient. We already established that Dependency Injection helps us to inject our components with services we use. For getting access to our new service, we need to add it to the provider list in our AppModule: [ And just to give you some understanding of what Environment files are here, they are actually included in the project on compilation phase, and.
You can use values from that file in all parts of your project and include them from environment. NgFor only supports binding to Iterables such as Arrays. Why so? We are getting observables from the Firebase. State is a single, immutable data structure —at least the way Ngrx implements it for us. This makes it all but impossible to store our application state in our State. But not completely—every single state is immutable, but the Store, which is our way of accessing State, is actually an Observable of the states.
So State is a single value in a stream of Store values. Both are immutable, but the second is based on the first, so instead of mutating values on our State, we create a new State object. For that, we use Reducers as pure functions , meaning that for any given State and Action and its payload reducer, it will return the same state as in any other call of that reducer function with same parameters.
What is happening there? Now I can tell you, Angular is a super solid and stable framework you would love to work with.
Forget what you heard about Angular 2 syntax a year ago, things looked different than you were used to in Angular 1 and no doubt you may feel confused. Current versions of Angular 5 had evolved to the point where you will be quickly impressed. When it all started, this framework was called AngularJS, and alludes to what we now know as Angular 1.
Then, Angular 2 arrived as a complete rewrite of the framework, improving from lessons learned and promising performance improvements, and a more scalable and more modern framework.
The first version of Angular was named Angular 2. From now on, every time we use the term Angular we are referring to the latest version of the framework including Angular 2, Angular 4 and Angular 5. More information about the latest versions: There were some major changes, but mostly on the project structure with lots of refactors that made the framework more stable.
Angular 5 is full of new features, bug fixes, performance improvements, and some code deprecation as a clean up of the refactors from version 4. You can find more information about these latest changes in this wonderful answer from stackoverflow. After the previous introduction about the current state of the Angular Framework, we are now ready to get started working on our angular 5 app. The best way to learn Angular is by following this step by step tutorial for beginners. In the following section of this angular free course we will go through the setup and requirements needed to start developing Angular apps.
Angular Site Template is our latest Angular 7 template and includes tons of use cases implemented the Angular way such as authentication flows, product listing, filtering, forms, routing guards and more.
In this section we will show you how to setup your local development environment so you can start developing Angular apps. A real application development happens in a local development environment that could be your personal machine.
Verify that you are running node 6. Older versions may produce errors, but newer versions are always recommended. Angular apps are created and developed primarily through the Angular CLI command line interface tool that helps project creation, adding files, and performing a variety of ongoing development tasks.
The Angular CLI takes care of configuration and initialization of various libraries. It also helps us adding components, directives, services, etc, to already existing Angular applications.
It includes everything you need to start writing your Angular 2 application right away. Important note: Now that you have Angular and its dependencies installed, we can move on and start building our Angular app. Starting a new angular app with the CLI is easy! From your command line, run this command: The Angular CLI does this for you:. You can also use the ng init command. The difference between ng init and ng new is that ng new requires you to specify the folder name and it will create a folder copying the files while ng init will copy the files to the current folder.
Now, you can cd into the created folder. To get a quick preview of your app inside the browser, use the serve command use ng serve. This command runs the compiler in watch mode looks for changes in the code and recompiles if needed , starts the server, launches the app in a browser, and keeps the app running while we continue building it.
Hence, if you open the url http: The new Angular CLI also has more tools to help you out with this.
For example, the new generator functions. They provide an easy way to create angular pages and services for your app. This makes going from a basic app to a full featured navigation web app much easier. I call that an easy learning curve: The angular-CLI will add a reference to components, directives and pipes automatically in the app. Please refer to angular CLI documentation for more information about adding components and other elements to your app.
The example app aims to help you learn the fundamental concepts of Angular Framework. The plan for this tutorial is to build an app that takes you step-by-step from setup to a full-featured example that serves to demonstrate the essential characteristics of a professional application: We will learn enough core Angular to get started and gain the confidence that Angular can do whatever we need it to do. We will be covering a lot of ground at an introductory level but we will also link to plenty of references to topics with greater depth.
In the next tutorial we will explore how to add a backend for this Angular app, using the MEAN stack. Angular is a framework designed to build single page applications SPAs and most of its architecture design is focused towards doing that in an effective manner. Single-page application or SPA are applications that are accessed via web browser like other websites but offer more dynamic interactions resembling native mobile and desktop apps.
The most notable difference between a regular website and SPA is the reduced amount of page refreshes. Typically, 95 percent of SPA code runs in the browser; the rest works in the server when the user needs new data or must perform secured operations such as authentication.
Modules help organize an application into cohesive functionality blocks by wrapping components, pipes, directives, and services. They are just all about developer ergonomics. Angular applications are modular. Every Angular application has at least one module— the root module, conventionally named AppModule. The root module can be the only module in a small application, but most apps have many more modules. As the developer, it's up to you to decide how to use the modules.
They are basically used for attaching metadata to classes so that it knows the configuration of those classes and how they should work.
The NgModule decorator properties that describe the module are:. Components are the most basic building block of an UI and Angular applications. A component controls one or more sections on the screen what we call views. A component is self contained and represents a reusable piece of UI that is usually constituted by three important things:.
Using the Angular Component decorator we provide additional metadata that determines how the component should be processed, instantiated and used at runtime.
For example we set the html template related to the view, then, we set the html selector that we are going to use for that component, we set stylesheets for that component. The Component passes data to the view using a process called Data Binding.
Binding can be used to display property values to the user, change element styles, respond to an user event, etc. A component must belong to an NgModule in order for it to be usable by another component or application. To specify that a component is a member of an NgModule , you should list it in the declarations property of that NgModule.
One side note on the components importance from a point of software architecture principles: Imagine we have two different UI blocks in the same component and in the same file. At the beginning, they may be small but each could grow. We are sure to receive new requirements for one and not the other.
Yet every change puts both components at risk and doubles the testing burden without any benefits. If we had to reuse some of those UI blocks elsewhere in our app, the other one would be glued along.
That scenario violates the Single Responsibility Principle. You may think this is only a tutorial, but we need to do things right — especially if doing them right is easy and we learn how to build Angular apps in the process.
A typical Angular application looks like a tree of components. The following diagram illustrates this concept. Note that the modal components are on the side of the parent component because they are imperative components which are not declared on the component html template.
Templates are used to define a component view. A template looks like regular HTML, but it also has some differences. These components mix seamlessly with native HTML in the same layouts. Almost anything can be a service, any value, function, or feature that your application needs.
A service is typically a class with a narrow, well-defined purpose. It should do something specific and do it well. The main purpose of Angular Services is sharing resources across components.
Take Component classes, they should be lean, component's job is to enable the user experience mediate between the view and the application logic and nothing more.
They don't fetch data from the server, validate user input, or log directly to the console. They delegate such tasks and everything nontrivial to services.
Services are fundamental to any Angular application, and components are big consumers of services as they help them being lean. Angular doesn't enforce these principles, but it helps you follow these principles by making it easy to structure your application logic into services and make those services available to components through dependency injection. In our example app we have three services: