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AngularJS Hosting Europe - HostForLIFE :: IoC Providers in Angular Dependency Injection useClass

clock October 9, 2024 09:04 by author Peter

Manual Injection of Class
Before we dive deep into Angular providers, let’s see how to create an Angular provider by ourselves. Please take a look at the below screenshot. We have created an interface named IManualService. We have two classes implementing the IManualService interface: ManualService and ManualServiceWithLog.

import { InjectionToken } from '@angular/core';
export const MANUAL_SERVICE_TOKEN = new InjectionToken<IManualService>(
  'MANUAL_SERVICE_TOKEN'
);
interface IManualService {
  name: string;
}
export class ManualService implements IManualService {
  public name = 'Manual Service';
  constructor() {}
}
export class ManualServiceWithLog implements IManualService {
  public name = 'Manual Service with logging feature';
  constructor() {
    console.log('I am manual service class with logging feature');
  }
}


For the dependency injection to work, we need to take care of three steps.
Define a Token: Define a token with a name for the injection. The token name is used by IoC to identify the class that needs to be injected whenever the particular token is requested.
    export const MANUAL_SERVICE_TOKEN = new InjectionToken<IManualService>(
      'MANUAL_SERVICE_TOKEN'
    );


Provide the Injection: The provider is the place where we define which class/value needs to be provided whenever we are requesting for a class/value.

Injecting ManualService class

import { ApplicationConfig } from '@angular/core';
import { provideRouter } from '@angular/router';

import { routes } from './app.routes';
import {
  MANUAL_SERVICE_TOKEN,
  ManualService,
  ManualServiceWithLog,
} from './services/manual-service/manual-service';

export const appConfig: ApplicationConfig = {
  providers: [
    provideRouter(routes),
    {
      provide: MANUAL_SERVICE_TOKEN,
      useClass: ManualService,
    },
  ],
};

Injecting ManualServiceWithLog class
import { ApplicationConfig } from '@angular/core';
import { provideRouter } from '@angular/router';

import { routes } from './app.routes';
import {
  MANUAL_SERVICE_TOKEN,
  ManualService,
  ManualServiceWithLog,
} from './services/manual-service/manual-service';

export const appConfig: ApplicationConfig = {
  providers: [
    provideRouter(routes),
    {
      provide: MANUAL_SERVICE_TOKEN,
      useClass: ManualServiceWithLog,
    },
  ],
};

Inject the Token: Inject the token in our component or elsewhere wherever we are using it.
constructor(
   @Inject(MANUAL_SERVICE_TOKEN) private manualService: ManualService
 )

import { Component, Inject, Injectable } from '@angular/core';
import {
  MANUAL_SERVICE_TOKEN,
  ManualService,
} from '../services/manual-service/manual-service';

@Component({
  selector: 'app-books-cart',
  standalone: true,
  imports: [],
  templateUrl: './books-cart.component.html',
})
export class BooksCartComponent {
  value: string = '';
  constructor(
    @Inject(MANUAL_SERVICE_TOKEN) private manualService: ManualService
  ) {
    this.value = manualService.name;
  }
}


Once we take care of the above steps, we are ready with dependency injection. Since I am using Angular 18, the latest version, I am using app.config.ts to configure the providers. Here in this app.config.ts, for the key MANUAL_SERVICE_TOKEN, I am passing the ManualService class.

You can see the name ‘Manual Service’ populating from the ManualService class being printed in the UI. In the app.routes.ts class, instead of passing the ManualService class, if you pass the ManualServiceWithLog class, you can see that name being printed as ‘Manual Service with Logging Feature’. Along with that, we can even observe that the console is being logged.

UI Output while using ManualService Class


UI Output while using ManualServiceWithLog.


I hope from this example, you have understood how to use Dependency Injection in Angular and the use of useClass in providers.



AngularJS Hosting Europe - HostForLIFE :: How to Create Mobile App with Angular Ionic?

clock October 1, 2024 07:54 by author Peter

We will discover how to use the Ionic framework to construct a mobile application in this tutorial. With the help of the open-source Ionic user interface tool, which integrates with well-known frameworks like Angular, React, and Vue, we can create professional mobile applications with HTML, CSS, and JavaScript.


Both iOS and Android are supported.

Pre-requisite
To start with Ionic Framework, the only requirement is a Node & npm environment, Andriod Studio, command line interface, and Visual Studio code as a code editor.

Step 1. Install ionic
The first step is we need to install ionic tooling. Run the below command to install ionic CLI.

  • native-run: Used to run native binaries on devices and simulators/emulators.
  • cordova-res: Used to generate icons and splash screens for the native app.

npm install -g @ionic/cli native-run cordova-res

Step 2. Create an Application
Run the below command to create an ionic application. We will create a calculator for this article’s explanation. Check out the below screen prints for command execution.

ionic start calculator

Step 3. Write an Application Code
home.page.html
<ion-header [translucent]="true">
  <ion-toolbar>
    <ion-title>
      Calculator
    </ion-title>
  </ion-toolbar>
</ion-header>

<ion-content [fullscreen]="true">
  <ion-header collapse="condense">
    <ion-toolbar>
      <ion-title size="large">Blank</ion-title>
    </ion-toolbar>
  </ion-header>

  <div id="container">
    <div class="jumbotron col-sm-4 p-2 m-0 bg-inverse mx-auto" style="border: 1px solid lightgray; border-radius: 2%;">
      <label style="font-weight: bolder;">Input</label>
      <div class="input-group input-group-sm col-sm-12 m-0 p-0">
        <div class="col-sm-12 form-control text-lg-right" type="text">{{input}}</div>
      </div>
      <label style="font-weight: bolder;">Result</label>
      <div class="input-group input-group-sm col-sm-12 m-0 p-0">
        <div class="form-control text-sm-right" type="text">{{result}}</div>
      </div>
      <div class="col-sm-12 p-1 m-0">
        <button class="btn btn-info col-sm-6" type="button" (click)="allClear()">C</button>
        <button class="btn btn-warning col-sm-3" type="button" (click)="clear()">x</button>
        <button class="btn btn-secondary col-sm-3" type="button" (click)="pressOperator('/')">/</button>
      </div>
      <div class="col-sm-12 p-1 m-0">
        <button class="btn btn-outline-secondary col-sm-3 p-1" type="button" (click)="clickNum('7')">7</button>
        <button class="btn btn-outline-secondary col-sm-3 p-1" type="button" (click)="clickNum('8')">8</button>
        <button class="btn btn-outline-secondary col-sm-3 p-1" type="button" (click)="clickNum('9')">9</button>
        <button class="btn btn-secondary col-sm-3 p-1" type="button" (click)="pressOperator('*')">X</button>
      </div>
      <div class="col-sm-12 p-1 m-0">
        <button class="btn btn-outline-secondary col-sm-3 p-1" type="button" (click)="clickNum('4')">4</button>
        <button class="btn btn-outline-secondary col-sm-3 p-1" type="button" (click)="clickNum('5')">5</button>
        <button class="btn btn-outline-secondary col-sm-3 p-1" type="button" (click)="clickNum('6')">6</button>
        <button class="btn btn-secondary col-sm-3 p-1" type="button" (click)="pressOperator('-')">-</button>
      </div>
      <div class="col-sm-12 p-1 m-0">
        <button class="btn btn-outline-secondary col-sm-3 p-1" type="button" (click)="clickNum('1')">1</button>
        <button class="btn btn-outline-secondary col-sm-3 p-1" type="button" (click)="clickNum('2')">2</button>
        <button class="btn btn-outline-secondary col-sm-3 p-1" type="button" (click)="clickNum('3')">3</button>
        <button class="btn btn-secondary col-sm-3 p-1" type="button" (click)="pressOperator('+')">+</button>
      </div>
      <div class="col-sm-12 p-1 m-0">
        <button class="btn btn-outline-secondary col-sm-3 p-1" type="button" (click)="clickNum('.')">.</button>
        <button class="btn btn-outline-secondary col-sm-3 p-1" type="button" (click)="clickNum('0')">0</button>
        <button class="btn btn-success col-sm-6 p-1" type="button" (click)="getAnswer()">=</button>
      </div>
    </div>
  </div>
</ion-content>


home.page.ts
import { Component } from '@angular/core';

@Component({
  selector: 'app-home',
  templateUrl: 'home.page.html',
  styleUrls: ['home.page.scss'],
})
export class HomePage {
  input: string = '';
  result: string = '';

  clickNum(num: string) {
    // Do Not Allow . more than once
    if (num == ".") {
      if (this.input != "") {
        const lastNum = this.getLastOperand();
        console.log(lastNum.lastIndexOf("."));
        if (lastNum.lastIndexOf(".") >= 0) return;
      }
    }

    // Do Not Allow 0 at beginning.
    // Javascript will throw Octal literals are not allowed in strict mode.
    if (num == "0") {
      if (this.input == "") {
        return;
      }
      const PrevKey = this.input[this.input.length - 1];
      if (PrevKey === '/' || PrevKey === '*' || PrevKey === '-' || PrevKey === '+') {
        return;
      }
    }

    this.input = this.input + num;
    this.calcAnswer();
  }

  getLastOperand() {
    let pos: number;
    console.log(this.input);
    pos = this.input.toString().lastIndexOf("+");
    if (this.input.toString().lastIndexOf("-") > pos) pos = this.input.lastIndexOf("-");
    if (this.input.toString().lastIndexOf("*") > pos) pos = this.input.lastIndexOf("*");
    if (this.input.toString().lastIndexOf("/") > pos) pos = this.input.lastIndexOf("/");
    console.log('Last ' + this.input.substr(pos + 1));
    return this.input.substr(pos + 1);
  }

  pressOperator(op: string) {
    // Do not allow operators more than once
    const lastKey = this.input[this.input.length - 1];
    if (lastKey === '/' || lastKey === '*' || lastKey === '-' || lastKey === '+') {
      return;
    }

    this.input = this.input + op;
    this.calcAnswer();
  }

  clear() {
    if (this.input != "") {
      this.input = this.input.substr(0, this.input.length - 1);
    }
  }

  allClear() {
    this.result = '';
    this.input = '';
  }

  calcAnswer() {
    let formula = this.input;

    let lastKey = formula[formula.length - 1];

    if (lastKey === '.') {
      formula = formula.substr(0, formula.length - 1);
    }

    lastKey = formula[formula.length - 1];

    if (lastKey === '/' || lastKey === '*' || lastKey === '-' || lastKey === '+' || lastKey === '.') {
      formula = formula.substr(0, formula.length - 1);
    }

    console.log("Formula " + formula);
    this.result = eval(formula);
  }

  getAnswer() {
    this.calcAnswer();
    this.input = this.result;
    if (this.input == "0") this.input = "";
  }
}

home.page.scss
#container {
  text-align: center;

  position: absolute;
  left: 0;
  right: 0;
  top: 50%;
  transform: translateY(-50%);
}

#container strong {
  font-size: 20px;
  line-height: 26px;
}

#container p {
  font-size: 16px;
  line-height: 22px;

  color: #8c8c8c;

  margin: 0;
}

#container a {
  text-decoration: none;
}

.col-sm-3 {
  flex: 0 0 auto;
  width: 23%;
  margin: 1%;
}

@media (min-width: 576px) {
  .col-sm-3 {
      flex: 0 0 auto;
      width: 23%;
      margin: 1%;
  }
}

.form-control{
  min-height: 30px;
}


Step 4. Add required packages
We can add third-party packages as per requirements. Here for this demo, I have used Bootstrap to make the UI smooth. Run the below command to install the Bootstrap.

Move to the application path using the below command.
cd calculator
npm i bootstrap bootstrap-icons
ng add @ng-bootstrap/ng-bootstrap

Import bootstrap to styles.scss file located at the root level.

Step 5. Run the Application with Browser
Run the below command to execute the application in a browser.
ionic serve


You can examine the folder structure and the created/generated www folder as soon as the application launches in the browser. All of the JavaScript code generated for the application is stored in the www folder. This is a www, similar to the dist folder in an Angular application. For an example, view the screen print below.


Step 6. Install the Android SDK
Once all application runs on the browser, we now need to run the same application on mobile devices like iOS or Android. For this article demonstration, I’m using an Android device. So I’ll generate the .apk file.

Now, let’s see how we can generate the APK file.

Let’s first run the below command in the terminal of the application path to generate apk.
ionic capacitor build android

If Android Studio is installed it will show a response like the below screen print, otherwise, you need to install Android Studio.


On My machine, I have already Android Studio installed. But you can get Android Studio from the mentioned path and get installed like the below screen print


Android Studio SDK path. Sometimes it takes time to download all required packages and it throws errors like the below screen print.

You can just close the error popup and close the project. It will start downloading pending packages and once all required packages are installed it will show a screen like below with the SDK path.


Step 7. Build the APK
Once the Android studio setup is done we can build apk file. To build apk file go to android studio -> build -> Build App Bundle(s) / APK(s) -> Build APK(s)

While building apk it will show the status like the below screen print.

Once APK generated you can click on locate and see the apk file.

Let’s install the APK file on an Android device.

Installed calculator application then let’s run application on the Android mobile device.




AngularJS Hosting Europe - HostForLIFE :: Combining jQuery Select2 with AngularJS for Dropdown Modifications

clock September 6, 2024 09:21 by author Peter

In contemporary web development, integrating many libraries and frameworks is frequently necessary to provide a seamless user experience. Combining AngularJS with jQuery Select2 to improve dropdown menus is one typical use case. This post looks at how to properly handle dropdown changes and synchronize AngularJS models with Select2.


Overview
For creating dynamic online applications, AngularJS is a strong framework. On the other hand, jQuery Select2 is a well-liked library that offers improved dropdown menu features like searching, tagging, and more. By combining these technologies, a strong user interface with cutting-edge features can be produced.

Setting up the Environment
First, ensure you have included the necessary libraries in your project.

  • AngularJS: For data binding and MVC functionality.
  • jQuery: Required by Select2 for DOM manipulation.

Select2: For advanced dropdown functionality
code
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.1.0/jquery.min.js"></script>
<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.5.5/angular.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/select2/4.0.3/js/select2.min.js"></script>
<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/select2/4.0.3/css/select2.min.css" />

<div class="col-md-3 mt-3">
    <label class="text-muted font-weight-bold">demoDis*</label>
    <select id="txtID" name="txtID" class="form-control select2" ng-model="Refundval" ng-options="lobjdata.Value as lobjdata.Name for lobjdata in ListMaster">
        <option value="" disabled selected hidden>Select</option>
    </select>
    <input type="hidden" id="hdRefundID" ng-model="hdRefundID" value="" />
</div>

app.controller('MyController', function($scope) {
    // Function to initialize Select2 and handle changes
    $scope.demoBan = function() {
        debugger;
        var Reta = JSON.parse(localStorage.getItem("Get"));
        console.log("RetailerId", RetailerId);
        $scope.ListMaster = Reta;
        angular.element(document).ready(function() {
            // Initialize Select2
            $('#txtID').select2();

            $('#txtID').on('change.select2', function() {
                var selectedValue = $(this).val();
                var selectedText = $('#txtID option:selected').text(); // Get the text of the selected option
                $scope.$applyAsync(function() {
                    // Update AngularJS model
                    $scope.Id = selectedValue;
                    $scope.Text = selectedText.trim(); // Store the text of the selected option
                    console.log("Selected Value:", selectedValue);
                    console.log("Selected Text:", $scope.Text);
                });
            });
        });
    };
});


Explanation

  • Initialization: Use angular. element(document).ready() to ensure that the DOM is fully loaded before initializing Select2.
  • Handling Changes: Bind to Select2’s change event to capture user selections. Use $scope.$applyAsync() to update AngularJS models and ensure the changes are reflected in the view.

Conclusion
Integrating AngularJS with Select2 can significantly enhance the user experience by combining Angular’s data binding capabilities with Select2’s advanced dropdown features. By following the steps outlined, you can effectively synchronize models between AngularJS and Select2, providing a seamless interaction for your users.



AngularJS Hosting Europe - HostForLIFE :: Various Methods in Angular for Redirecting and Retrieving ID Parameters

clock September 3, 2024 08:03 by author Peter

Angular is a potent front-end framework that offers numerous methods for data passing, including ID parameters, and component navigation. Whether you're developing a sophisticated enterprise application or a single-page application (SPA), handling routing correctly requires knowing how to extract parameters and redirect users.


1. Using Basic Navigation with the RouterLink Directive

In Angular, the easiest way to move between components is with the RouterLink directive. It assists in creating URLs with dynamic parameters and is utilized directly in templates.

<a [routerLink]="['/employee', employee.id]">View Details</a>

The employee.id is appended to the /employee route, creating a dynamic URL like /employee/123. This is a convenient way to navigate when the route parameters are known within the template.

2. Programmatic Navigation with the Router
For more complex scenarios, such as navigation that depends on some business logic or conditional operations, Angular’s Router service can be used for programmatic navigation.
import { Router } from '@angular/router';
constructor(private router: Router) {}
viewEmployeeDetails(employeeId: number) {
  this.router.navigate(['/employee', employeeId]);
}


navigate() method takes an array where the first element is the route path, and the subsequent elements are the route parameters.

3. Retrieving Parameters Using ActivatedRoute
Once you’ve navigated to a route that includes parameters, you'll often need to retrieve those parameters in the component. Angular provides the ActivatedRoute service for this purpose.
import { ActivatedRoute } from '@angular/router';
constructor(private route: ActivatedRoute) {}
ngOnInit(): void {
  const employeeId = this.route.snapshot.paramMap.get('id');
  console.log('Employee ID:', employeeId);
}

snapshot.paramMap.get('id') retrieves the id parameter from the route. This is a synchronous method, meaning it grabs the parameter value only at the moment of the component's creation.

4. Using Observables for Dynamic Parameter Retrieval

While snapshot is useful for simple use cases, Angular applications often require handling route changes dynamically without destroying and recreating components. This is where paramMap as an Observable comes into play.
import { ActivatedRoute } from '@angular/router';
constructor(private route: ActivatedRoute) {}
ngOnInit(): void {
  this.route.paramMap.subscribe(params => {
    const employeeId = params.get('id');
    console.log('Employee ID:', employeeId);
  });
}


paramMap.subscribe() ensures that every time the id parameter changes, the new value is logged or processed accordingly. This is ideal for components that need to respond to route changes dynamically.

5. Combining Query Parameters with Navigation
Sometimes, you may want to navigate to a route and include additional information via query parameters. Angular’s Router service allows combining both route parameters and query parameters.
this.router.navigate(['/employee', employeeId], { queryParams: { ref: 'dashboard' } });

navigation directs to /employee/123?ref=dashboard, where 123 is the route parameter, and ref=dashboard is a query parameter.

If you want to retrieve the query parameters in the component
this.route.queryParams.subscribe(params => {
  const ref = params['ref'];
  console.log('Referred from:', ref);
});

6. Redirection after Form Submission
Another common use case is redirecting the user after a form submission or some action completion.
onSubmit() {
  // Assuming form submission is successful
  this.router.navigate(['/employee', newEmployeeId]);
}


7. Handling Complex Redirections with Guards
Angular also supports complex redirection scenarios using route guards. Guards can intercept navigation and redirect users based on certain conditions.
import { Injectable } from '@angular/core';
import { CanActivate, Router } from '@angular/router';
@Injectable({
  providedIn: 'root'
})
export class AuthGuard implements CanActivate {
  constructor(private router: Router) {}
  canActivate(): boolean {
    if (isLoggedIn()) {
      return true;
    } else {
      this.router.navigate(['/login']);
      return false;
    }
  }
}


if the is logged in () function returns false, the user is redirected to the /login route, preventing unauthorized access.

Conclusion
Navigating between routes and handling parameters in Angular is a fundamental aspect of building dynamic and user-friendly applications. Whether you use the simple RouterLink, programmatic navigation, or complex redirection logic, Angular provides the tools to handle a wide range of routing scenarios efficiently.

Happy Coding!



AngularJS Hosting Europe - HostForLIFE :: Knowing Angular vs. React

clock August 19, 2024 10:08 by author Peter

React and Angular are two of the most widely used front-end frameworks for creating contemporary online apps. Both are supported by sizable groups and have distinct advantages, yet they serve varying needs and tastes. We'll go over the main distinctions between Angular and React in this post to assist you in choosing the right framework for your project.

 

Overview

  1. React
    • Developed by: Facebook
    • Initial Release: 2013
    • Type: JavaScript library for building user interfaces, primarily focused on rendering UI components.
    • Learning Curve: Moderate
    • Main Concept: React is centered around components and follows a unidirectional data flow.
  2. Angular
    • Developed by: Google
    • Initial Release: 2016 (as Angular 2, the complete rewrite of AngularJS)
    • Type: Full-fledged framework for building web applications.
    • Learning Curve: Steep
    • Main Concept: Angular is an opinionated framework that provides a comprehensive solution for building large-scale applications, including built-in features like routing, state management, and HTTP services.

Architecture

  1. React
    • Component-Based: React is all about components. Each piece of UI is a component that can manage its state and be reused throughout the application.
    • Virtual DOM: React uses a virtual DOM to optimize rendering performance. When the state of a component changes, React updates the virtual DOM and then efficiently updates the real DOM.
    • Flexibility: React offers flexibility by allowing developers to choose their own libraries for routing, state management, and other needs. This makes React a "view library" rather than a full-fledged framework.
  2. Angular
    • MVC Architecture: Angular follows the Model-View-Controller (MVC) pattern, which helps in separating the concerns of data (Model), UI (View), and logic (Controller).
    • Real DOM: Unlike React, Angular directly interacts with the real DOM, which can impact performance in complex applications. However, Angular mitigates this with its change detection mechanism.
    • Built-In Features: Angular comes with a range of built-in features like form validation, HTTP client, routing, and RxJS for reactive programming. This makes Angular a complete solution for building applications without relying on external libraries.

Performance

  1. React
    • Virtual DOM: React’s virtual DOM significantly improves performance by minimizing the number of direct manipulations to the real DOM.
    • Component Reusability: React’s component-based architecture promotes reusability, which can lead to better performance in large applications.
    • Bundle Size: React itself is relatively lightweight, but depending on the additional libraries you use, the bundle size can grow.
  2. Angular
    • Change Detection: Angular’s change detection mechanism can sometimes lead to performance bottlenecks in large applications, but it also provides tools like OnPush strategy and NgZone to optimize performance.
    • Ahead-of-Time (AOT) Compilation: Angular’s AOT compilation improves performance by compiling the application during the build process, reducing the load time.
    • Built-In Features: While Angular’s rich feature set can impact performance, the framework’s ability to optimize these features mitigates the impact.

Learning Curve

  1. React
    • JSX: React uses JSX, a syntax extension that allows you to write HTML within JavaScript. While some developers find JSX intuitive, others might find it challenging initially.
    • Flexibility: React’s flexibility means you need to learn how to integrate and use various libraries for routing, state management, etc., which can be both an advantage and a challenge.
    • Documentation and Community: React has extensive documentation and a large community, making it easier to find resources, tutorials, and third-party libraries.
  2. Angular
    • Steep Learning Curve: Angular has a steeper learning curve due to its complexity and the number of built-in features you need to understand.
    • TypeScript: Angular is built with TypeScript, a statically typed superset of JavaScript. While this adds benefits like better tooling and error checking, it also requires learning TypeScript if you’re not already familiar with it.
    • Comprehensive Framework: Angular’s opinionated nature means that once you learn the Angular way of doing things, you have a powerful set of tools at your disposal.

Ecosystem and Community

  1. React
    • Ecosystem: React has a rich ecosystem with numerous libraries for state management (Redux, MobX), routing (React Router), and more. The flexibility to choose different tools gives developers more control over their stack.
    • Community: React has a large and active community, contributing to a vast array of plugins, tools, and resources.
  2. Angular
    • Ecosystem: Angular has a more integrated ecosystem. Many features that require third-party libraries in React are built into Angular, such as routing, HTTP services, and form handling.
    • Community: Angular also has a large community, but it is more centralized around the official Angular resources, documentation, and Google-backed initiatives.

Use Cases
 

React

  1. When to Use React
    • You need flexibility in choosing libraries and tools.
    • You prefer a simple, component-based architecture.
    • You are building a project where performance and simplicity are key.
  2. Popular Use Cases
    • Single-page applications (SPAs)
    • Static sites with dynamic components
    • Dashboards and data visualization tools

Angular

  1. When to Use Angular
    • You are building a large-scale, enterprise-level application.
    • You need a framework with a comprehensive set of tools and built-in features.
    • You prefer an opinionated framework that guides architectural decisions.
  2. Popular Use Cases
    • Complex, enterprise-level applications
    • Applications requiring robust form handling and validation
    • Real-time applications with complex state management

Conclusion
The skills of your team and the needs of your project will determine which of React and Angular is best. React is an excellent option for projects where you want more control over the architecture because of its simplicity and versatility. In contrast, Angular offers a feature-rich, opinionated framework right out of the box, making it perfect for enterprise-level apps. Both Angular and React are effective front-end development tools, and knowing the advantages and disadvantages of each will help you choose wisely for your upcoming project.



AngularJS Hosting Europe - HostForLIFE :: Angular Routing Mastery Navigate Between Components Easily

clock August 16, 2024 09:34 by author Peter

Routing in Angular enables you to move between several parts (or views) in a single-page application (SPA). To do this, routes that associate URL pathways with particular components are built up. The relevant component loads and displays in a preset area of your application (typically designated by a <router-outlet>) when a user navigates to a URL.


to use the robust routing system of Angular to move between components in an efficient manner. This article covers everything from configuring routes to using Angular's Router service programmatically and utilizing RouterLink for template-based navigation. You will learn how to map URLs to components and render them dynamically using <router-outlet>, providing smooth navigation inside your Angular applications, with concise explanations and functional code examples.

Key Concepts

  1. Router Module: This is Angular's mechanism for handling routing. You define the routes in a routing module (often AppRoutingModule), where each route maps a URL path to a component.
  2. RouterLink Directive: This directive is used in HTML templates to bind a URL to an anchor tag or button. When clicked, Angular will navigate to the route specified by the RouterLink.
  3. Router Service: This service provides methods to navigate to a route programmatically from within a component’s TypeScript file.
  4. Router Outlet: This is a directive that acts as a placeholder where the routed component will be rendered.

Step-by-Step Implementation with Code Example
1. Setting Up Routes

First, create your components if you haven't already.
ng generate component component-a
ng generate component component-b


Then, define the routes in the AppRoutingModule.
import { NgModule } from '@angular/core';
import { RouterModule, Routes } from '@angular/router';
import { ComponentA } from './component-a/component-a.component';
import { ComponentB } from './component-b/component-b.component';

const routes: Routes = [
  { path: 'component-a', component: ComponentA },
  { path: 'component-b', component: ComponentB },
  { path: '', redirectTo: '/component-a', pathMatch: 'full' }  // Default route
];

@NgModule({
  imports: [RouterModule.forRoot(routes)],
  exports: [RouterModule]
})
export class AppRoutingModule { }

2. Navigating Using RouterLink

In ComponentA, you can create a link that navigates to ComponentB.
<!-- component-a.component.html -->
<h2>This is Component A</h2>
<a [routerLink]="['/component-b']">Go to Component B</a>


When the user clicks on this link, Angular will navigate to /component-b and load ComponentB into the router outlet.

3. Navigating Programmatically Using the Router Service

You can also navigate programmatically from within a component’s TypeScript file.

// component-a.component.ts
import { Component } from '@angular/core';
import { Router } from '@angular/router';

@Component({
  selector: 'app-component-a',
  templateUrl: './component-a.component.html',
  styleUrls: ['./component-a.component.css']
})
export class ComponentA {

  constructor(private router: Router) { }

  goToComponentB() {
    this.router.navigate(['/component-b']);
  }
}


In the corresponding HTML.
<!-- component-a.component.html -->
<h2>This is Component A</h2>
<button (click)="goToComponentB()">Go to Component B</button>


4. Using Router Outlet
Ensure you have a <router-outlet> in your main HTML template (usually app.component.html).
<!-- app.component.html -->
<router-outlet></router-outlet>

This directive is where the routed components will be displayed based on the URL.

5. Putting It All Together

Here’s how everything ties together.

  • AppRoutingModule: Defines the routes.
  • ComponentA: Has a link and a button to navigate to ComponentB.
  • ComponentB: Displays content when navigated to.

Example Code Structure// app-routing.module.ts
import { NgModule } from '@angular/core';
import { RouterModule, Routes } from '@angular/router';
import { ComponentA } from './component-a/component-a.component';
import { ComponentB } from './component-b/component-b.component';

const routes: Routes = [
  { path: 'component-a', component: ComponentA },
  { path: 'component-b', component: ComponentB },
  { path: '', redirectTo: '/component-a', pathMatch: 'full' }  // Default route
];

@NgModule({
  imports: [RouterModule.forRoot(routes)],
  exports: [RouterModule]
})
export class AppRoutingModule { }

// component-a.component.ts
import { Component } from '@angular/core';
import { Router } from '@angular/router';

@Component({
  selector: 'app-component-a',
  templateUrl: './component-a.component.html',
  styleUrls: ['./component-a.component.css']
})
export class ComponentA {

  constructor(private router: Router) { }

  goToComponentB() {
    this.router.navigate(['/component-b']);
  }
}

// component-a.component.html
<h2>This is Component A</h2>
<a [routerLink]="['/component-b']">Go to Component B</a>
<button (click)="goToComponentB()">Go to Component B</button>

// component-b.component.html
<h2>This is Component B</h2>

// app.component.html
<router-outlet></router-outlet>

Summary

  • Routes: Define in AppRoutingModule to map URLs to components.
  • RouterLink: Use templates for simple navigation.
  • Router Service: Use for programmatic navigation in TypeScript.
  • Router Outlet: The placeholder for rendering routed components.

This setup allows you to navigate between components effectively, using both template-based and programmatic methods in Angular.



AngularJS Hosting Europe - HostForLIFE :: Angular SSR (server-side rendering)

clock August 12, 2024 10:21 by author Peter

Angular Universal provides server-side rendering (SSR) capabilities for Angular applications. SSR improves performance and SEO by rendering the initial HTML on the server before sending it to the client. This documentation outlines the steps to implement Angular SSR using Angular Universal.

What is client-side rendering (CSR)?
Client-side rendering (CSR) is the process of rendering web pages in the browser using JavaScript. The server sends a minimal HTML file along with JavaScript, which then dynamically generates and updates the content. This approach enables more interactive and responsive web pages by allowing specific parts of the page to be updated without a full page reload.


Server-side rendering (SSR): what is it?
The process of rendering web pages on the server and delivering the completely rendered HTML to the client is known as server-side rendering, or SSR. With this method, the client receives the HTML page in its entirety, generated by the server together with any dynamic data. After that, the client shows the page without doing any additional processing.


Steps to implement Angular SSR using Angular Universal.

Step 1. Set Up Angular Application

Create a new Angular application if you don't have one already.
ng new project-name

Step 2. Add Angular Universal
Add Angular Universal to your application.
ng add @nguniversal/express-engine

Step 3. Add non-destructive hydration

To enable non-destructive hydration, we need to import the provideClientHydration function as the provider of AppModule.
import { provideClientHydration } from '@angular/platform-browser';
// ...

@NgModule({
  // ...
  providers: [provideClientHydration()],  // add this line
  bootstrap: [AppComponent]
})
export class AppModule {
  // ...
}

Step 4. Update the Angular Configuration

Ensure your angular.json includes SSR configurations. This should be done automatically when you add Angular Universal.

Step 5. Update Server Files
const ssrRoutes = ['/test'];

// All regular routes use the Universal engine
server.get('*', (req, res) => {
  if (ssrRoutes.some((route) => req.url.startsWith(route))) {
    res.render(indexHtml, {
      req,
      providers: [{ provide: APP_BASE_HREF, useValue: req.baseUrl }]
    });
  } else {
    res.sendFile(join(distFolder, 'index.html'));
  }
});

Step 6. Serve the Application

npm run dev:ssr

Conclusion

By following these steps, you can implement server-side rendering in your Angular application using Angular Universal. SSR enhances performance and improves SEO by serving pre-rendered HTML content to the client.



AngularJS Hosting Europe - HostForLIFE :: Harnessing the Power of Environments using Angular

clock August 5, 2024 08:40 by author Peter

Ever pondered how to call multiple APIs, colors, or headlines for the same application from several environments? Production APIs and test APIs are undoubtedly distinct and need to be utilized extremely carefully. When launching a project, we won't manually alter every API call and sentence structure. This is dangerous and should not be done. With Angular, it's simple to have distinct setups for various environments. Because of this, we can use and deploy to as many environments and stages as necessary without ever having to alter the code. Environment files is the name of it.


To put it briefly, we can have two environment files: environment.development.ts for the development stage and environment.ts for the production stage. The appropriate environment file will then be used, based on where we are distributing our program.

There are very few configurations needed, and there is a significant gain. I'll walk you through the process in this post and give an example of using various texts and APIs.

Getting started
Create a new app: ng new angular-environment-demo --standalone false.
Generate environment files: ng generate environments.

Note. As from the Angular 15.1 environment files are not generated automatically.

Environment file hierarchy
The identical item will initially be present in both the environments.ts and the environments.development.ts. Both objects should have the same key and all settings should be done with them.

For example, you have the following in that file if the environment.development.ts has a key-value pair like: "weather_status": "Good" and the environment.ts will not utilize it. The weather status is ''. This is due to the fact that you are using it in the code, and your code will utilize [this will be explained later] when it looks for it in the environment file. Compilation errors result from your code still searching for this even if it is pointing to another environment file.

Let's create two distinct page titles.

You can utilize the environment file's values in the app.component.ts file or any other ts file by accessing them as follows: environment.\<value you wish to access.>>. Here's an illustration of how to use the pageTitle in the app.component.ts ngOnInit.

Notice the import on line 2. For now, you can import any of the environment files. On line 13, we are assigning the value of ‘pageTitle’ from the environment to ‘this. title’. In the HTML file, we are using the ‘title’ as below.

When you serve the application using: ng serve, you will be given the following screen.

When we do only: “ng serve”, the values from the ‘environment.development.ts’ file are used. If you want to use the configurations from the environment.ts file, you should add the following in the angular.json file.

"fileReplacements": [
  {
    "replace": "src/environments/environment.development.ts",
    "with": "src/environments/environment.ts"
  }
],


These codes should be added under "projects" -> "architect" -> "build" -> "configurations" -> "production" in the angular.json file. Below is a full example of the angular.json file:

{
  "$schema": "./node_modules/@angular/cli/lib/config/schema.json",
  "version": 1,
  "newProjectRoot": "projects",
  "projects": {
    "angular-environment-demo": {
      "projectType": "application",
      "schematics": {
        "@schematics/angular:component": {
          "standalone": false
        },
        "@schematics/angular:directive": {
          "standalone": false
        },
        "@schematics/angular:pipe": {
          "standalone": false
        }
      },
      "root": "",
      "sourceRoot": "src",
      "prefix": "app",
      "architect": {
        "build": {
          "builder": "@angular-devkit/build-angular:application",
          "options": {
            "outputPath": "dist/angular-environment-demo",
            "index": "src/index.html",
            "browser": "src/main.ts",
            "polyfills": [
              "zone.js"
            ],
            "tsConfig": "tsconfig.app.json",
            "assets": [
              "src/favicon.ico",
              "src/assets"
            ],
            "styles": [
              "src/styles.css"
            ],
            "scripts": []
          },
          "configurations": {
            "stagging": {
              "fileReplacements": [
                {
                  "replace": "src/environments/environment.ts",
                  "with": "src/environments/environment.stagging.ts"
                }
              ]
            },
            "production": {
              "budgets": [
                {
                  "type": "initial",
                  "maximumWarning": "500kb",
                  "maximumError": "1mb"
                },
                {
                  "type": "anyComponentStyle",
                  "maximumWarning": "2kb",
                  "maximumError": "4kb"
                }
              ],
              "fileReplacements": [
                {
                  "replace": "src/environments/environment.development.ts",
                  "with": "src/environments/environment.ts"
                }
              ],
              "outputHashing": "all"
            },
            "development": {
              "optimization": false,
              "extractLicenses": false,
              "sourceMap": true,
              "fileReplacements": [
                {
                  "replace": "src/environments/environment.ts",
                  "with": "src/environments/environment.development.ts"
                }
              ]
            }
          },
          "defaultConfiguration": "production"
        },
        "serve": {
          "builder": "@angular-devkit/build-angular:dev-server",
          "configurations": {
            "stagging": {
              "buildTarget": "angular-environment-demo:build:stagging"
            },
            "production": {
              "buildTarget": "angular-environment-demo:build:production"
            },
            "development": {
              "buildTarget": "angular-environment-demo:build:development"
            }
          },
          "defaultConfiguration": "development"
        },
        "extract-i18n": {
          "builder": "@angular-devkit/build-angular:extract-i18n",
          "options": {
            "buildTarget": "angular-environment-demo:build"
          }
        },
        "test": {
          "builder": "@angular-devkit/build-angular:karma",
          "options": {
            "polyfills": [
              "zone.js",
              "zone.js/testing"
            ],
            "tsConfig": "tsconfig.spec.json",
            "assets": [
              "src/favicon.ico",
              "src/assets"
            ],
            "styles": [
              "src/styles.css"
            ],
            "scripts": []
          }
        }
      }
    }
  }
}

This file is the most important one when we want to make the best use of an environment file. To use the configuration from the environment.ts file, we need to serve the application with the following command: “ng serve --configuration=production”.

Note that you did not make any changes in the code, you have added only a new configuration and served the app using the new command. For example, if you are serving in production, you can use this command to serve in that environment. No changes in the code are required. It is common to have multiple environments used mostly for testing. When you need to accommodate a new environment, there are some steps to follow.

create a new environment file in the environment folder. For example, we can add environment.staging.ts.
Once this is created, do not forget to add values present in other environment files.

In the angular.json file, we need to add a new configuration under configuration.

The last part is still in the angular.json file. Now we need to add the configuration to serve the application using the respective environment file. These changes are done under "projects" -> "architect" -> "serve" -> "configurations"

We use the following command to serve the application using the settings found in the environment.stagging.ts file: ng serve --configuration=stagging. The screen that loads after serving is as follows.


Using environment files to use different APIs. Another powerful application of environment files is how easily, almost seamlessly it can be used to call different APIs for different environments.

Below are the steps.
Add the corresponding key-value pair in the environment object in all the environment files in your project, like below.
export const environment = {
    pageTitle: "Dinosaur",
    apiUrl: "https://dinosaur-facts-api.shultzlab.com/dinosaurs"
};

In your component.ts file, wherever required, you can call the web service in any method that you want.
For this example, we will be using the fetch method in a promise.
getInfo(){
  const myPromise = new Promise((resolve, reject) => {
    fetch(environment.apiUrl)
    .then((response) => response.json())
    .then((data) => {
      resolve(data)
    })
    .catch((error) => reject(error))
  });

  myPromise
  .then((result: any) => {
    const element = document.getElementById('txtResult');
    if (element) {
      element.innerHTML = JSON.stringify(result.slice(0, 5));
    }
    console.log(result.slice(0, 5));
  })
  .catch((error) => console.log(error))
  .finally(() => console.log('promise done'));
}

Notice that in the call, we are not passing any api. Instead, we are using the variable from the environment file.
At this point, the function is done and can be called when a button is clicked.
When we serve the application using: ng serve and click on the button, we get the following.

When we serve the application using ng serve --configuration=production, below is the output:

  • Note that there has been NO code change. We have only served the application using different serving configurations.
  • The same applies when you are deploying to an environment. Whether you are deploying your Angular app using Azure or something else, you are asked at some point the command to run the Angular application. Providing the correct serving configuration will use the required environment file and will display the corresponding information or call the desired API. No changes in code are required.

Conclusion
Environment files are very important and powerful. Maximizing their use will prevent you from doing manual changes when deploying in different stages.



AngularJS Hosting Europe - HostForLIFE :: How to Copying Text to Clipboard in AngularJS?

clock August 1, 2024 08:52 by author Peter

Web applications frequently need users to copy text to the clipboard in order to share links, copy codes, or accomplish other tasks. We will look at how to add a copy-to-clipboard feature to an AngularJS application in this article.

Required conditions
You need know the fundamentals of JavaScript and AngularJS in order to follow along with this lesson.

Step 1: Configuring the AngularJS Program

Let's start by configuring a basic AngularJS application. Ensure that your HTML file has the AngularJS library.

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Copy to Clipboard in AngularJS</title>
    <script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.8.2/angular.min.js"></script>
</head>
<body ng-app="clipboardApp" ng-controller="clipboardController">
    <!-- Your AngularJS app content will go here -->
</body>
</html>

Step 2. Creating the AngularJS Module and Controller
Next, let's create an AngularJS module and a controller.
<script>
    var app = angular.module('clipboardApp', []);

    app.controller('clipboardController', ['$scope', function($scope) {
        $scope.textToCopy = "Hello, this is the text to be copied!";

        $scope.copyToClipboard = function() {
            var textArea = document.createElement("textarea");
            textArea.value = $scope.textToCopy;
            document.body.appendChild(textArea);
            textArea.select();

            try {
                document.execCommand('copy');
                alert('Text copied to clipboard');
            } catch (err) {
                console.error('Unable to copy', err);
            }

            document.body.removeChild(textArea);
        };
    }]);
</script>

Step 3. Adding the HTML Elements
Now, let's add the HTML elements to allow users to copy the text.
<div class="container">
    <h1>Copy to Clipboard Example</h1>
    <div class="form-group">
        <label for="textToCopy">Text to Copy:</label>
        <input
            type="text"
            id="textToCopy"
            ng-model="textToCopy"
            class="form-control"
            readonly
        >
    </div>
    <button
        ng-click="copyToClipboard()"
        class="btn btn-primary"
    >
        Copy to Clipboard
    </button>
</div>


Explanation

  • Creating a Textarea Element: In the copy to clipboard function, we create a textarea element dynamically and set its value to the text we want to copy.
  • Appending Textarea to Body: The textarea is appended to the body of the document to ensure it is part of the DOM.
  • Selecting the Text: We then select the text inside the text area.
  • Copying the Text: Using document.execCommand('copy'), we copy the selected text to the clipboard.
  • Removing the Textarea: Finally, we remove the textarea element from the document.


Step 4. Styling the Application
You can add some CSS to style the application.
<style>
    .container {
        margin: 50px;
    }

    .form-group {
        margin-bottom: 20px;
    }

    .btn-primary {
        background-color: #007bff;
        border-color: #007bff;
    }
</style>


Example 1

Conclusions

You can incorporate copy-to-clipboard capabilities into your AngularJS application with ease by following these steps. This feature makes it easier for users to copy text without having to pick and paste it by hand, which improves user experience. Play around with this implementation and adjust it to suit the requirements of your application.



AngularJS Hosting Europe - HostForLIFE :: Using Services to Make Angular API Calls

clock July 25, 2024 07:31 by author Peter

Working with APIs is a standard chore in modern web development. Angular's HttpClient module offers a reliable method for managing HTTP requests. You will learn how to create an Angular service that will call an API and manage the responses in this tutorial.

Configuring Angular Project
Make sure you have Angular CLI installed before we begin. If not, you can use the following command to install it.
npm install -g @angular/cli

Create a new Angular project.
ng new api-service-demo
cd api-service-demo


Add HttpClientModule to your project.
ng add @angular/common/http

Creating the Service
Generate a new service using Angular CLI.
ng generate service api

This command will create a file named api.service.ts in the src/app directory.

Importing HttpClient

First, import HttpClient and HttpClientModule in your app.module.ts.
import { HttpClientModule } from '@angular/common/http';

@NgModule({
  declarations: [
    // Your components
  ],
  imports: [
    BrowserModule,
    HttpClientModule,
    // Other modules
  ],
  providers: [],
  bootstrap: [AppComponent]
})
export class AppModule { }


Implementing the API Call in the Service
Next, implement the API call in your service (api.service.ts).
import { Injectable } from '@angular/core';
import { HttpClient } from '@angular/common/http';
import { Observable } from 'rxjs';

@Injectable({
  providedIn: 'root'
})
export class ApiService {

  private apiUrl = 'https://jsonplaceholder.typicode.com/posts'; // Replace with your API URL

  constructor(private http: HttpClient) { }

  getPosts(): Observable<any> {
    return this.http.get<any>(this.apiUrl);
  }
}


In this example, getPosts is a method that sends a GET request to the specified API URL and returns an Observable of the response.

Using the Service in a Component

Now, let's use this service in a component to fetch data and display it. Generate a new component.ng generate component post-list
Injecting the Service
Inject the ApiService in your post-list.component.ts.import { Component, OnInit } from '@angular/core';
import { ApiService } from '../api.service';

@Component({
  selector: 'app-post-list',
  templateUrl: './post-list.component.html',
  styleUrls: ['./post-list.component.css']
})
export class PostListComponent implements OnInit {

  posts: any[] = [];

  constructor(private apiService: ApiService) { }

  ngOnInit(): void {
    this.apiService.getPosts().subscribe(data => {
      this.posts = data;
    });
  }
}
Displaying Data in the TemplateUpdate the template (post-list.component.html) to display the fetched data.<div *ngIf="posts.length > 0">
  <h2>Posts</h2>
  <ul>
    <li *ngFor="let post of posts">
      <h3>{{ post.title }}</h3>
      <p>{{ post.body }}</p>
    </li>
  </ul>
</div>
<div *ngIf="posts.length === 0">
  <p>No posts available.</p>
</div>


Running the Application
Serve the Angular application using the following command.
ng serve

Navigate to http://localhost:4200 in your browser to see the list of posts fetched from the API.

Conclusion
In this article, we've covered how to make API calls in Angular using a service. We created a service to handle HTTP requests and used this service in a component to fetch and display data. This approach ensures that your API logic is centralized and reusable across different components.



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