Angular Meets RxJS: Basic Concepts

Introduction to basic concepts of reactive programming with RxJS such as observables, observers and subscriptions

Introduction

I’m working with “Angular” since the version 1.4 and I really enjoy it. It’s when I had switch to Angular 2 that I first heard about “RxJS” and reactive programming. I’m a bit ashamed to admit that my first reaction was to tell myself “who cares? I can build nice applications without it”… And I was not wrong… Indeed, it’s possible to create nice applications without “RxJS”, the same way it’s possible to be a very good golf player using a broom stick. At the end of the day, even though you learnt to play very well with the stick, making the effort to learn to play with a regular golf club will help you getting even better.

That’s the same with “RxJS” in “Angular”. Even though nothing forces you to use it (well… To be totally honest, the “HttpClient” implementation kind of forces you to), you’ll be way more effective and your application will be way more reactive if you master it.

My reluctance to learn how to use this awesome library was a lot correlated to the fact that, let’s admit it, it’s not the easiest library to master (even now I wouldn’t say that I master it). However, this also comes from the fact that the reactive programming approach is very different of every programming style I used to use.

This is why I decided to write a series of article guiding you through the journey of learning how to use “RxJS” in an efficient way in an “Angular” application. I don’t say that what you’re going to learn is the only way of using “RxJS” but it’s how I do it and so far, it seems pretty reliable.

In this article…

All right, here we go… The topic of this article is not the funniest thing ever. Indeed, before being able to start using “RxJS”, it’s better to understand the theory behind it. I’ll try not to overwhelm you with a ton of information, instead, I’ll give you the bare minimum theory you’ll need in the current article, then I’ll spread the bits that I left off in the next articles. So straighten up little solider and be brave, once you got through this article, you’ll be ready to have some fun with a lot of programming :-)

Reactive programming

The “Rx” in “RxJS” actually stands for “ReactiveX” which is a set of tools that you can use to do reactive programming. Indeed, you have to know that reactive programming is not specific to “JavaScript”. You can do reactive programming with “Java” using the “RxJava” library or in C## using the “System.Reactive” package. This means that “RxJS” is “just” the library to use in “JavaScript” to do reactive programming.

#angular #rxjs #javascript #web-development #programming

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Angular Meets RxJS: Basic Concepts
Roberta  Ward

Roberta Ward

1593184320

Basics of Angular: Part-1

What is Angular? What it does? How we implement it in a project? So, here are some basics of angular to let you learn more about angular.

Angular is a Typescript-based open-source front-end web application platform. The Angular Team at Google and a community of individuals and corporations lead it. Angular lets you extend HTML’s syntax to express your apps’ components clearly. The angular resolves challenges while developing a single page and cross-platform applications. So, here the meaning of the single-page applications in angular is that the index.html file serves the app. And, the index.html file links other files to it.

We build angular applications with basic concepts which are NgModules. It provides a compilation context for components. At the beginning of an angular project, the command-line interface provides a built-in component which is the root component. But, NgModule can add a number of additional components. These can be created through a template or loaded from a router. This is what a compilation context about.

What is a Component in Angular?

Components are key features in Angular. It controls a patch of the screen called a view. A couple of components that we create on our own helps to build a whole application. In the end, the root component or the app component holds our entire application. The component has its business logic that it does to support the view inside the class. The class interacts with the view through an API of properties and methods. All the components added by us in the application are not linked to the index.html. But, they link to the app.component.html through the selectors. A component can be a component and not only a typescript class by adding a decorator @Component. Then, for further access, a class can import it. The decorator contains some metadata like selector, template, and style. Here’s an example of how a component decorator looks like:

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

Role of App Module

Modules are the package of functionalities of our app. It gives Angular the information about which features does my app has and what feature it uses. It is an empty Typescript class, but we transform it by adding a decorator @NgModule. So, we have four properties that we set up on the object pass to @NgModule. The four properties are declarations, imports, providers, and bootstrap. All the built-in new components add up to the declarations array in @NgModule.

@NgModule({
declarations: [
  AppComponent,
],
imports: [
  BrowserModule,
  HttpClientModule,
  AppRoutingModule,
  FormsModule
],
bootstrap: [AppComponent]
})

What is Data Binding?

Data Binding is the communication between the Typescript code of the component and the template. So, we have different kinds of data binding given below:

  • When there is a requirement to output data from our Typescript code in the HTML template. String interpolation handles this purpose like {{data}} in HTML file. Property Binding is also used for this purpose like [property] = “data”.
  • When we want to trigger any event like clicking a button. Event Binding works while we react to user events like (event) = “expression”.
  • When we can react to user events and output something at the same time. Two-way Binding is used like [(ngModel)] = “data”.

image for understanding data binding

#angular #javascript #tech blogs #user interface (ui) #angular #angular fundamentals #angular tutorial #basics of angular

Christa  Stehr

Christa Stehr

1598940617

Install Angular - Angular Environment Setup Process

Angular is a TypeScript based framework that works in synchronization with HTML, CSS, and JavaScript. To work with angular, domain knowledge of these 3 is required.

  1. Installing Node.js and npm
  2. Installing Angular CLI
  3. Creating workspace
  4. Deploying your First App

In this article, you will get to know about the Angular Environment setup process. After reading this article, you will be able to install, setup, create, and launch your own application in Angular. So let’s start!!!

Angular environment setup

Install Angular in Easy Steps

For Installing Angular on your Machine, there are 2 prerequisites:

  • Node.js
  • npm Package Manager
Node.js

First you need to have Node.js installed as Angular require current, active LTS or maintenance LTS version of Node.js

Download and Install Node.js version suitable for your machine’s operating system.

Npm Package Manager

Angular, Angular CLI and Angular applications are dependent on npm packages. By installing Node.js, you have automatically installed the npm Package manager which will be the base for installing angular in your system. To check the presence of npm client and Angular version check of npm client, run this command:

  1. npm -v

Installing Angular CLI

  • Open Terminal/Command Prompt
  • To install Angular CLI, run the below command:
  1. npm install -g @angular/cli

installing angular CLI

· After executing the command, Angular CLI will get installed within some time. You can check it using the following command

  1. ng --version

Workspace Creation

Now as your Angular CLI is installed, you need to create a workspace to work upon your application. Methods for it are:

  • Using CLI
  • Using Visual Studio Code
1. Using CLI

To create a workspace:

  • Navigate to the desired directory where you want to create your workspace using cd command in the Terminal/Command prompt
  • Then in the directory write this command on your terminal and provide the name of the app which you want to create. In my case I have mentioned DataFlair:
  1. Ng new YourAppName

create angular workspace

  • After running this command, it will prompt you to select from various options about the CSS and other functionalities.

angular CSS options

  • To leave everything to default, simply press the Enter or the Return key.

angular setup

#angular tutorials #angular cli install #angular environment setup #angular version check #download angular #install angular #install angular cli

Monty  Boehm

Monty Boehm

1625113066

Angular Basics: Refresh an Angular Component Without Reloading the Same Component

A short trick for refreshing Angular components in generic way.

If you are working with Angular and need to refresh a component without navigation on another component without using window.location.reload() orlocation.reload(), you can use the following code in your project:

mySubscription: any;

Then, add this code to the required component’s constructor.

this.router.routeReuseStrategy.shouldReuseRoute = function () {
  return false;
};
this.mySubscription = this.router.events.subscribe((event) => {
  if (event instanceof NavigationEnd) {
    // Trick the Router into believing it's last link wasn't previously loaded
    this.router.navigated = false;
  }
});

#angular-basics #angular #angular-concepts

Sasha  Roberts

Sasha Roberts

1626834660

Angular Rxjs: Use .map() And Async Pipe (Refactor Your Code)

In this video, we will see how to improve our code using the #rxs map operator and #angular #async pipe.

The components should be clean and minimal and should not have code that manipulates the data. Responsible for data manipulation is a service.
The goal is to prepare our data and return an #observable pipe so that we can use an #async pipe in the template.

code: https://github.com/profanis/codeShotsWithProfanis/tree/13/rxjsMapAndAsyncPipe

#angular #rxjs #observable #map #async

#angular rxjs #angular #angular tutorial #what is angular

Angular Meets RxJS: Basic Concepts

Introduction to basic concepts of reactive programming with RxJS such as observables, observers and subscriptions

Introduction

I’m working with “Angular” since the version 1.4 and I really enjoy it. It’s when I had switch to Angular 2 that I first heard about “RxJS” and reactive programming. I’m a bit ashamed to admit that my first reaction was to tell myself “who cares? I can build nice applications without it”… And I was not wrong… Indeed, it’s possible to create nice applications without “RxJS”, the same way it’s possible to be a very good golf player using a broom stick. At the end of the day, even though you learnt to play very well with the stick, making the effort to learn to play with a regular golf club will help you getting even better.

That’s the same with “RxJS” in “Angular”. Even though nothing forces you to use it (well… To be totally honest, the “HttpClient” implementation kind of forces you to), you’ll be way more effective and your application will be way more reactive if you master it.

My reluctance to learn how to use this awesome library was a lot correlated to the fact that, let’s admit it, it’s not the easiest library to master (even now I wouldn’t say that I master it). However, this also comes from the fact that the reactive programming approach is very different of every programming style I used to use.

This is why I decided to write a series of article guiding you through the journey of learning how to use “RxJS” in an efficient way in an “Angular” application. I don’t say that what you’re going to learn is the only way of using “RxJS” but it’s how I do it and so far, it seems pretty reliable.

In this article…

All right, here we go… The topic of this article is not the funniest thing ever. Indeed, before being able to start using “RxJS”, it’s better to understand the theory behind it. I’ll try not to overwhelm you with a ton of information, instead, I’ll give you the bare minimum theory you’ll need in the current article, then I’ll spread the bits that I left off in the next articles. So straighten up little solider and be brave, once you got through this article, you’ll be ready to have some fun with a lot of programming :-)

Reactive programming

The “Rx” in “RxJS” actually stands for “ReactiveX” which is a set of tools that you can use to do reactive programming. Indeed, you have to know that reactive programming is not specific to “JavaScript”. You can do reactive programming with “Java” using the “RxJava” library or in C## using the “System.Reactive” package. This means that “RxJS” is “just” the library to use in “JavaScript” to do reactive programming.

#angular #rxjs #javascript #web-development #programming