Demystifying angular/router: what is RouterScroller and why is it useful ?

The RouterScroller entity is a very interesting part of the Angular Router. In this post, we’re going to have a look at how it works, what makes its features possible and how it can be configured, depending on the developer’s needs.

The RouterScroller entity is a very interesting part of the Angular Router. In this post, we’re going to have a look at how it works, what makes its features possible and how it can be configured, depending on the developer’s needs.

It helps us achieve things like scrolling to a fragment, setting an offset for that fragment and, lastly, navigating back to where the browser left off as a result of a popstate event.

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How RouterScroller is set up#

Files referenced in this section: router_module, router_scroller.

Since the @angular/router is a built-in package provided by Angular, is has to go through a process of initialization, in order to make sure everything is set up correctly. In this case, it happens inside a APP_BOOTSTRAP_LISTENER’s listener. If we peek at the source code, we can see that the first lines of the function’s block are just this.injector.get calls:

const opts = this.injector.get(ROUTER_CONFIGURATION);
const preloader = this.injector.get(RouterPreloader);
const routerScroller = this.injector.get(RouterScroller);
const router = this.injector.get(Router);
const ref = this.injector.get<ApplicationRef>(ApplicationRef);

/* ... */
<>

This might seem trivial at first sight, but some of the arguments provided to this.injector.get are in fact factory tokens, meaning that some piece of logic will run in order to retrieve what has been asked for.

For example, RouterScroller(the article’s focal point) is defined as follows:

{
  provide: RouterScroller,
  useFactory: createRouterScroller,
  deps: [Router, ViewportScroller, ROUTER_CONFIGURATION]
},
<>

createRouterScroller will simply create an instance of the RouterScroller class, based on the ROUTER_CONFIGURATION token. This can be seen in the class’ constructor:

constructor(
    private router: Router,
    public readonly viewportScroller: ViewportScroller, private options: {
      scrollPositionRestoration?: 'disabled'|'enabled'|'top',
      anchorScrolling?: 'disabled'|'enabled'
    } = {}) {
  // Default both options to 'disabled'
  options.scrollPositionRestoration = options.scrollPositionRestoration || 'disabled';
  options.anchorScrolling = options.anchorScrolling || 'disabled';
}
<>

Then, after the Router is initialized (Router.initialNavigation), the RouterScroller will be initialized as well, with RouterScroller.init():

init(): void {
  // we want to disable the automatic scrolling because having two places
  // responsible for scrolling results race conditions, especially given
  // that browser don't implement this behavior consistently
  if (this.options.scrollPositionRestoration !== 'disabled') {
    this.viewportScroller.setHistoryScrollRestoration('manual');
  }

  this.routerEventsSubscription = this.createScrollEvents();
  this.scrollEventsSubscription = this.consumeScrollEvents();
}
<>

The last two lines represent the gist of RouterScroller. We are going to explore them in the following section, along with some examples.

#angular #angular-router

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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!!!

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

· 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

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

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

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

Demystifying angular/router: what is RouterScroller and why is it useful ?

The RouterScroller entity is a very interesting part of the Angular Router. In this post, we’re going to have a look at how it works, what makes its features possible and how it can be configured, depending on the developer’s needs.

The RouterScroller entity is a very interesting part of the Angular Router. In this post, we’re going to have a look at how it works, what makes its features possible and how it can be configured, depending on the developer’s needs.

It helps us achieve things like scrolling to a fragment, setting an offset for that fragment and, lastly, navigating back to where the browser left off as a result of a popstate event.

THIS AD MAKES CONTENT FREE. HIDE

How RouterScroller is set up#

Files referenced in this section: router_module, router_scroller.

Since the @angular/router is a built-in package provided by Angular, is has to go through a process of initialization, in order to make sure everything is set up correctly. In this case, it happens inside a APP_BOOTSTRAP_LISTENER’s listener. If we peek at the source code, we can see that the first lines of the function’s block are just this.injector.get calls:

const opts = this.injector.get(ROUTER_CONFIGURATION);
const preloader = this.injector.get(RouterPreloader);
const routerScroller = this.injector.get(RouterScroller);
const router = this.injector.get(Router);
const ref = this.injector.get<ApplicationRef>(ApplicationRef);

/* ... */
<>

This might seem trivial at first sight, but some of the arguments provided to this.injector.get are in fact factory tokens, meaning that some piece of logic will run in order to retrieve what has been asked for.

For example, RouterScroller(the article’s focal point) is defined as follows:

{
  provide: RouterScroller,
  useFactory: createRouterScroller,
  deps: [Router, ViewportScroller, ROUTER_CONFIGURATION]
},
<>

createRouterScroller will simply create an instance of the RouterScroller class, based on the ROUTER_CONFIGURATION token. This can be seen in the class’ constructor:

constructor(
    private router: Router,
    public readonly viewportScroller: ViewportScroller, private options: {
      scrollPositionRestoration?: 'disabled'|'enabled'|'top',
      anchorScrolling?: 'disabled'|'enabled'
    } = {}) {
  // Default both options to 'disabled'
  options.scrollPositionRestoration = options.scrollPositionRestoration || 'disabled';
  options.anchorScrolling = options.anchorScrolling || 'disabled';
}
<>

Then, after the Router is initialized (Router.initialNavigation), the RouterScroller will be initialized as well, with RouterScroller.init():

init(): void {
  // we want to disable the automatic scrolling because having two places
  // responsible for scrolling results race conditions, especially given
  // that browser don't implement this behavior consistently
  if (this.options.scrollPositionRestoration !== 'disabled') {
    this.viewportScroller.setHistoryScrollRestoration('manual');
  }

  this.routerEventsSubscription = this.createScrollEvents();
  this.scrollEventsSubscription = this.consumeScrollEvents();
}
<>

The last two lines represent the gist of RouterScroller. We are going to explore them in the following section, along with some examples.

#angular #angular-router

Angular Material Autocomplete - Multiple Use Cases covered

Learn How to use Angular Material Autocomplete Suggestions Search Input. I covered multiple use cases.

Please watch this video. I hope this video would be helpful for you to understand it and use it in your projects

Please subscribe: https://www.youtube.com/channel/UCL5nKCmpReJZZMe9_bYR89w

#angular #angular-material #angular-js #autocomplete #angular-material-autocomplete #angular-tutorial

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”.

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

Angular Sass: How To Use Sass In Angular 9 Tutorial

Angular supports Sass, CSS, and Less to style global application styles as well as component styles. Angular components styles have an effective CSS encapsulation mechanism that assures any component CSS is local to the component and does not globally alter any styles.

Angular Sass Example

Why use Angular Sass? Well!! Sass (Syntactically Awesome Style Sheets) is an extension of CSS that allows you to use things like variables, nested rules, inline imports, and more. It also supports you to keep things organized and enables you to create style sheets faster.

In short,  Sass is a CSS preprocessor, which combines unique features such as variables, nested rules, and mixins (sometimes referred to as syntactic sugar) into regular CSS. The main object of Sass is to make the CSS coding process more comfortable and more efficient.

Sass is compatible with all versions of CSS. When working with the Angular CLI, the default stylesheets have the .css extension. We are using Angular CLI 8. So, if you have not used previously, then please upgrade your  CLI version. We will use the Bootstrap 4 Framework for this demo and see how we can configure the Sass in our Angular 9 application.

#angular #angular 9 #angular cli #css #angular sass