Angular ngOnChanges Lifecycle Method Example

Angular ngOnChanges is a lifecycle hook that is called when any data-bound property of a directive changes. To respond to changes to the @Input() variables, use the ngOnChanges() lifecycle hook. The ngOnChanges() takes the changes argument of type SimpleChanges.

Angular ngOnChanges

The ngOnChanges() is an inbuilt Angular callback method that is invoked immediately after the default change detector has checked data-bound properties if at least one has changed. Before the view and content, children are checked.

interface OnChanges {
  ngOnChanges(changes: SimpleChanges): void
}

Let’s understand this by an example.

Angular bydefault comes with AppComponent. It will act as a parent component.

Let’s create one more component called ChildComponent.

So, now we have two components.

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1. AppComponent: Parent Component
2. ChildComponent: Child Component

We define a property inside the Parent component and pass that property to Child component, and it will accept that property using @Input directive.

We modify the value of the property from the Parent and Child component.

Write the following code inside the **app.component.ts **file.

// app.component.ts

import { Component, OnInit } from '@angular/core';

@Component({
  selector: 'app-root',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.css']
})
export class AppComponent implements OnInit {
  data = 0;
  constructor() {
  }

  ngOnInit(): void {
  }

  changeFromParent(): void {
    this.data += 1;
  }
}

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We are defining a class property called **data **whose initial value is 0.Then we have defined a function called changeFromParent(), which is called when the button is clicked.

After the button is clicked, the value of the property will be modified, and it will add +1.

Write the following code inside the **app.component.html **file.

<!-- app.component.html -->

<div class="container">
  <div class="row">
    <div class="col-md-4">
      <a (click)="changeFromParent()" class="btn btn-success">Change from parent</a>
    </div>
    <div class="col-md-8">
      <app-child [parentData]=data></app-child>
    </div>
  </div>
</div>

We have used bootstrap 4 for styling our components.

In this code, we have defined a click event, and if it is fired, then the data property will be incremented by one, and it is defined inside the parent component.

We have also defined a Child component that accepts the parentData as input data from the Parent component.

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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.

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Angular 11 Google Social Login Example

Angular 9/10/11 social login with google using angularx-social-login library example. In this tutorial, i will show you step by step on how to implement google social login in angular 11 app.

And also, this tutorial will show you How to login into Angular 10/11 application with google using angularx-social-login library in angular 11 app.

Google Login Integration In Angular 11 App

• Step 1 - Create New Angular App
• Step 2 - Install Social Login Library
• Step 3 - Add Code on App.Module.ts File
• Step 4 - Add Code on View File
• Step 5 - Add Code On App.Component ts File
• Step 6 - Start the Angular Google Login App

https://www.tutsmake.com/angular-11-google-social-login-example/

#angular 11 google login #angular 11 social-login example #login with google button angular 8/9/10/11 #angular 10/11 login with google #angular 10 social google login #angular social login google

Angular 11 Facebook Social Login Example

Angular 9/10/11 social login with facebook using angularx-social-login library example. In this tutorial, i would love to show you how to integrate facebook social login in angular 11 app.

And you will learn how to add facebook social login button with angular reactive login form.

Angular 11 Social Login with Facebook Tutorial

• Step 1 - Create New Angular App
• Step 2 - Install Social Login Library
• Step 3 - Add Code on App.Module.ts File
• Step 4 - Add Code on View File
• Step 5 - Add Code On App.Component ts File
• Step 6 - Start the Angular Facebook Login App

https://www.tutsmake.com/angular-11-facebook-login-tutorial-example/

#angular 11 facebook login #angular 11 social-login example #login with facebook button angular 8/9/10/11 #angular 10/11 login with facebook #angular 10 social facebook login #angular social login facebook

Angular 11 Google Social Login Example Tutorial

Angular 9/10/11 social login with google using angularx-social-login library example. In this tutorial, i will show you step by step on how to implement google social login in angular 11 app.

And also, this tutorial will show you How to login into Angular 10/11 application with google using angularx-social-login library in angular 11 app.

Google Login Integration In Angular 11 App

• Step 1 - Create New Angular App
• Step 2 - Install Social Login Library
• Step 3 - Add Code on App.Module.ts File
• Step 4 - Add Code on View File
• Step 5 - Add Code On App.Component ts File
• Step 6 - Start the Angular Google Login App

https://www.tutsmake.com/angular-11-google-social-login-example/

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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”.

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