Angular Interview Questions and Answers for 2023 Web Development

Angular is a popular JavaScript framework for building web applications, and it is used by a wide range of organizations and developers. Some examples of companies and organizations that use Angular include: 

• Google: Angular was developed and is maintained by Google, and it is used by many Google products and services. 
• Microsoft: Angular is used by a number of Microsoft products and services, including Microsoft Teams and the Azure portal. 
• Netflix: The Netflix streaming service uses Angular to build its web applications. 
• Forbes: The Forbes website uses Angular to build its online content management system. 
• PayPal: The PayPal website uses Angular to build its web applications. 

These are just a few examples of the many companies and organizations that use Angular. Angular is a popular choice for building web applications because it provides a rich set of features for building client-side applications, including a powerful routing system, a comprehensive set of built-in directives, and a dependency injection system. It is widely used by developers around the world to build dynamic and interactive web applications. 

Angular is a JavaScript framework for building web applications. It is not related to the Java programming language. 

Angular is a front-end framework, which means that it runs in the user's web browser and is responsible for building the user interface of a web application. It is built using JavaScript, and it uses HTML and CSS to build the user interface of the application. 

Java, on the other hand, is a general-purpose programming language that is used to build a wide variety of applications, including web, mobile, and desktop applications. It is not specifically designed for building web applications, and it is not used in the same way as Angular.  

Overall, Angular is a powerful and popular JavaScript framework for building web applications, and it is not related to the Java programming language. 

It is not appropriate to say that Angular is "better" than HTML, as they serve different purposes and are used in different ways. 

HTML (HyperText Markup Language) is a markup language that is used to structure and format the content of a web page. It is the foundation of the modern web, and it is used to define the structure and layout of a web page, as well as the content that is displayed on the page.

Angular, on the other hand, is a JavaScript framework for building web applications. It is built on top of HTML and is used to create interactive and dynamic web applications. Angular provides a number of features and tools that make it easier to build complex web applications, including a powerful routing system, a comprehensive set of built-in directives, and a dependency injection system.

Overall, HTML and Angular are both important tools for building web applications, but they serve different purposes and are used in different ways. HTML is used to structure and format the content of a web page, while Angular is used to build interactive and dynamic web applications.

Angular is a framework for building web applications, not a scripting language.

A scripting language is a type of programming language that is often used to automate tasks and to add functionality to an existing application. Scripting languages are typically interpreted, meaning that the code is executed immediately, rather than being compiled into machine code. Examples of scripting languages include JavaScript, Python, and Perl.

On the other hand, Angular is a JavaScript-based framework for building web applications. It uses a component-based architecture to build reusable and modular code, and it also provides a set of tools and features for creating dynamic and interactive user interfaces. Angular provides a structure and a set of conventions to help you organize your code, and it also provides a set of built-in directives, services, and other features to help you create a web application easily. 

Angular is a JavaScript framework for building web applications. It allows you to use HTML as your template language and helps you extend HTML's syntax to express your application's components clearly and concisely. Angular is a complete rewrite of AngularJS, which was developed by Google. Angular is written in TypeScript, and it is a platform that is well-suited for building large applications with a complex structure. It provides a number of features that make it easy to develop and maintain such applications, including: 

• A declarative template syntax that makes it easy to define the structure of your application's UI. 
• A powerful dependency injection system that makes it easy to manage the relationships between different components of your application. 
• A reactive programming model that makes it easy to handle asynchronous events and manipulate data. 
• A rich set of built-in features, such as forms, routing, and HTTP communication, that you can use to build a wide range of applications. 
• Overall, Angular is a powerful and flexible platform that is well-suited for building modern, interactive web applications. 

AngularJS is a JavaScript framework for building web applications. It is open-source and was developed and maintained by Google. AngularJS allows developers to extend HTML by creating new custom elements and attributes using JavaScript, making it easier to create dynamic, interactive user interfaces. 

AngularJS uses a Model-View-Controller (MVC) architecture, which helps to separate the concerns of the application, such as data manipulation and presentation, making it easier to maintain and test the code. 

The framework provides a number of features that make it easier to build complex web applications, such as two-way data binding, dependency injection, and a powerful directive system. The two-way data binding feature allows changes in the model to be automatically reflected in the view, and vice versa, without the need to manually update the view every time the model changes. Dependency injection is a design pattern that makes it easy to manage dependencies between different components of an application. And the directive system allows you to create custom HTML elements that can be reused throughout the application. 

AngularJS also comes with a built-in set of directives and services that provide common functionality such as form validation, routing, and HTTP communication, allowing you to focus on building the unique functionality of your application. 

AngularJS has been widely adopted by many companies, and it is widely used by many web developer to build web application as well. In 2016, AngularJs released its next version Angular 2, Which was completely rebuilt with a different architecture and language syntax than AngularJS.

Angular and AngularJS are two different JavaScript frameworks for building web applications. AngularJS is the original version of Angular, which was released in 2010. Angular is a complete rewrite of AngularJS, released in 2016. 

There are a number of differences between Angular and AngularJS: 

• Architecture: Angular is based on a component-based architecture, while AngularJS is based on a model-view-controller (MVC) architecture. 
• Language: Angular is written in TypeScript, while AngularJS is written in JavaScript. 
• Templating: Angular uses a template language based on HTML, while AngularJS uses plain JavaScript with a special syntax for defining templates. 
• Testing: Angular provides a number of tools and features to make testing easier, such as a test runner and dependency injection. AngularJS has fewer built-in testing features. 

Overall, Angular is a more powerful and flexible framework than AngularJS, and it is the recommended choice for building modern web applications.

This is a frequently asked Angular Interview Question and often leads the conversation during any Angular interview.

Angular is a frontend framework used to develop single-page client applications or dynamic web applications with the use of 2 languages - TypeScript & HTM. It is a powerful and flexible platform that is well-suited for building large and complex applications. Angular provides a number of features that make it easy to develop and maintain such applications, including: 

• A declarative template syntax that makes it easy to define the structure of your application's UI. 
• A powerful dependency injection system that makes it easy to manage the relationships between different components of your application. 
• A reactive programming model that makes it easy to handle asynchronous events and manipulate data. 
• A rich set of built-in features, such as forms, routing, and HTTP communication, that you can use to build a wide range of applications. 

When it comes to questions related to the versions of Angular used by the particular organization, the difference between Angular 7 and Angular 8 is one of the most asked Angular interview questions for beginners. This is also one of the most popular Angular 8 interview questions to start with. Here are the top differences between these two Angular versions.

Angular 7:- 

• Angular 7 is not easy to use. 
• It supports most versions of Node.js. 
• It only supports basic Typescript 3.4 programming language. 

Angular 8:- 

• Angular 8 can be easily used. 
• Angular 8 only supports Node.js 12 version. 
• It does not support basic versions of the typescript 3.4 programming language.

In Angular, templates are used to define the structure of the user interface (UI) of an application. A template is a piece of HTML that defines the layout and content of a view. It can include static elements, such as text and images, as well as dynamic elements, such as loops and conditionals. 

Templates in Angular are declarative, which means that you can describe what you want the UI to look like without specifying how to create it. Angular uses the information in the template to generate the UI at runtime. This makes it easier to develop and maintain applications, because you can focus on the structure of the UI rather than the details of its implementation. 

Here is an example of a simple template in Angular that you may encounter in your angular coding interview question, for this here is the syntax: 

<div> 
  <h1>{{title}}</h1> 
  <p>Welcome to {{name}}</p> 
</div> 

In this example, title and name are variables that are bound to the template. The values of these variables are displayed in the template using double curly braces ({{ }}). W 

In Angular, an expression is a JavaScript-like code snippet that is evaluated at runtime. Expressions are used to bind values to HTML templates, and they can contain literals, operators, and variables. 

Expressions are written in templates using double curly braces ({{ }}). For example: 

<p>The value of x is {{x}}</p> 

In this example, x is a variable that is bound to the template. When the application is running, Angular will evaluate the expression {{x}} and replace it with the value of the x variable. 

Expressions can also contain operators and function calls. For example: 

<p>{{x + y}}</p> 
<p>{{getFullName(firstName, lastName)}}</p> 

In the first example, the + operator is used to add the values of x and y. In the second example, the getFullName function is called with the arguments firstName and lastName. 

Overall, expressions are a useful way to bind values to templates and create dynamic UI in Angular applications. 

The responses to the question "Why use Angular?" were provided by the state of JS 2018 survey to the developer community who use the Angular framework in their work.  

• Faster Development Process 
  • Detailed Documentation  
  • Angular CLI  
  • Two-Way Data Binding  
• Testable and Readable Code  
  • Modules  
  • Components  
• Lighter Weight Web Application 
  • Lazy-Load Modules 
  • Ivy Renderer 

Here are other advantages to using Angular for building web applications: 

• Angular is a powerful and flexible framework that is well-suited for building large and complex applications. It provides a number of features that make it easy to develop and maintain such applications, such as a declarative template syntax, a powerful dependency injection system, and a reactive programming model. 
• Angular is based on a component-based architecture, which makes it easy to reuse code and build modular applications. Components are independent and self-contained units of code that can be combined to build larger applications. 
• Angular provides a rich set of built-in features, such as forms, routing, and HTTP communication, that you can use to build a wide range of applications. It also has a large and active community that has developed a wide variety of third-party libraries and tools that can be used with Angular. 
• Angular is written in TypeScript, which is a superset of JavaScript that adds optional static typing and other features. TypeScript can help improve the reliability and maintainability of your code by catching errors at compile time rather than runtime. 
• Angular has a strong emphasis on testing, and it provides a number of tools and features to make testing easier, such as a test runner and dependency injection. This can help you build applications that are of high quality and easy to maintain.

Yes, AngularJS is designed to support multiple browsers. AngularJS is a JavaScript-based web framework that is used for building single-page applications (SPAs). It is designed to be cross-browser compatible, meaning that it can run on a variety of different web browsers, including modern browsers such as Google Chrome, Mozilla Firefox, and Apple Safari, as well as older browsers such as Internet Explorer. 

To ensure compatibility with a wide range of browsers, AngularJS includes a number of features and techniques that are designed to work around browser-specific quirks and differences. This includes techniques such as polyfills, which are used to provide support for features that are not available in all browsers, and automatic error handling, which helps to mitigate the impact of browser-specific issues on the application.

Angular is a JavaScript-based web framework that is often used for building single-page applications (SPAs). In the context of Angular applications, "authentication" refers to the process of verifying the identity of a user, while "authorization" refers to the process of determining whether a user has access to a particular resource or action. 

There are several ways to implement authentication and authorization in an Angular application, depending on the requirements of the application and the needs of the users. Some common approaches include: 

• Basic authentication: This is a simple authentication scheme that uses a username and password to authenticate users. In an Angular application, basic authentication can be implemented using the HTTP Basic authentication standard, which is supported by most web servers and browsers. 
• Token-based authentication: This is a more secure authentication scheme that uses JSON Web Tokens (JWTs) to authenticate users. In a token-based authentication system, the server issues a token to the client after the client has successfully authenticated, and the client includes the token in subsequent requests to the server. This allows the server to verify the identity of the client without requiring the client to send the username and password with every request. 
• OAuth: OAuth is a standard for authorization that allows users to grant access to their resources on one site (such as a social media platform) to another site (such as an Angular application) without giving away their username and password. OAuth can be used to implement single sign-on (SSO) and other authorization scenarios in Angular applications. 

In terms of authorization, Angular applications can use a variety of approaches to determine whether a user has access to a particular resource or action. This might include using role-based access controls, where users are assigned to specific roles that have different levels of access, or using more fine-grained access controls, where access to specific resources or actions is granted or denied on a case-by-case basis. 

• A.Parent to Child: via Input  
• Child to Parent: via Output() and EventEmitter  
• Child to Parent: via ViewChild  
• Unrelated Components: via a Service 

One of the most common Angular basic interview questions. Be prepared to answer this one. 

To answer this angular routing interview questions, an annotation is a way of adding metadata to a class, its members, or its methods. Annotations are not part of the class itself, but they provide additional information that can be used by Angular at runtime. 

Annotations in Angular are written in the form of a function that is called with a configuration object. For example: 

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

Here, the @Component annotation is adding metadata to the AppComponent class, indicating that it is a component and specifying the selector, template, and styles that should be used when rendering the component. 

On the other hand, a decorator is a function that modifies or adds functionality to a class, its members, or its methods. Decorators are a way to extend the behavior of a class without modifying the class itself. 

In Angular, decorators are often used to define the metadata for a class, similar to annotations. However, decorators can also be used to add additional functionality to a class, such as adding a property or method. 

For example, the following decorator adds a new method to a class: 

function log(target: any, key: string) { 
  console.log(key + ' has been called'); 
} 
class MyClass { 
  @log 
  sayHello() { 
    console.log('Hello'); 
  } 
} 

Here, the log decorator is used to add a new method to the MyClass class that logs a message to the console each time the sayHello method is called. 

In Angular, a directive is a class that can add behavior to an element, component, or another directive. Directives are a way to extend the template HTML with new syntax and attributes, and they can be used to manipulate the DOM, bind to data, and add logic to your templates. 

There are two types of directives in Angular: 

Components: A component is a directive that has a template, and it is the most common type of directive. Components are used to define reusable UI elements that can be composed to build complex user interfaces. 

Structural directives: A structural directive is a directive that changes the structure of the DOM by adding, removing, or manipulating elements. Structural directives are identified by a * prefix in the template HTML, such as *ngFor or *ngIf. 

To show how this works in your angular developer interview questions, Here is an example of a component directive: 

@Component({ 
  selector: 'app-my-component', 
  template: '<h1>My Component</h1>' 
}) 
export class MyComponent {} 
And here is an example of a structural directive: 
<ul> 
  <li *ngFor="let item of items">{{ item }}</li> 
</ul> 

In this example, the *ngFor directive is used to iterate over the items array and generate a list item for each element in the array. 

Directives are an important concept in Angular, as they allow you to extend the template HTML with new syntax and attributes, and add behavior to your templates. 

In Angular, a decorator is a function that modifies or adds functionality to a class, its members, or its methods. Decorators are a way to extend the behavior of a class without modifying the class itself. 

In Angular, decorators are often used to define the metadata for a class, such as the component selector, template, and styles. They are also used to add additional functionality to a class, such as adding a property or method. 

For example, the following decorator adds a new property to a class: 

function log(target: any, key: string) { 
  console.log(key + ' has been called'); 
} 
class MyClass { 
  @log 
  name: string; 
} 

Here, the log decorator is used to add a new property to the MyClass class that logs a message to the console each time the name property is accessed. 

Decorators are a powerful feature of Angular, and they are used extensively throughout the framework. They are a way to extend the behavior of a class without modifying the class itself, and they can be used to add metadata, add, or modify properties and methods, and customize the behavior of a class in various ways.

In such angular material interview questions, a filter is a way to transform or format the value of an expression for display to the user. Filters are often used to format dates, currency, and other values for display, and they can be used in templates, controllers, and services. 

To use a filter in Angular, you need to include the filter in the template HTML using the | character, followed by the filter name and any arguments. The value to be filtered is placed on the left side of the | character, and the filter is applied to the value. 

For example, the following template uses the date filter to format a date value: 

<p>Today is {{ today | date }}</p> 

In this example, the today value is a JavaScript Date object, and the date filter is used to format it as a short date string. 

Angular comes with a set of built-in filters, such as date, currency, and uppercase, and you can also create your own custom filters. 

Filters are a useful feature in Angular, as they allow you to transform and format values for display in a declarative way, without having to write complex formatting logic in your component classes. 

We must include $cookies in your controller, and the Get, Set, and Clear methods must be used to get, set, and clear cookies, respectively. Precise has inbuilt mandates named as ngCookies.

Reactive forms, also known as model-driven forms, are a way to build and manage forms in Angular. Unlike template-driven forms, which are based on directives and require you to specify the form controls and validation in the template HTML, reactive forms allow you to build the form in the component class and bind it to the template using a declarative syntax. 

Reactive forms are built using a reactive programming model, which means that the form and its controls are created as observables that can be subscribed to and modified over time. This makes reactive forms more flexible and easier to test than template-driven forms, as the form logic is kept in the component class and is not mixed with the template HTML. 

To use reactive forms in Angular, you need to import the ReactiveFormsModule from the @angular/forms module and add it to the imports array of your module. Then, you can create a form group in the component class and bind it to the template using the [formGroup] directive. 

Here is an example of a simple reactive form: 

import { Component } from '@angular/core'; 
import { FormGroup, FormControl } from '@angular/forms'; 
@Component({ 
  selector: 'app-my-form', 
  template: ` 
    <form [formGroup]="form"> 
      <input type="text" formControlName="name"> 
      <button type="submit">Submit</button> 
    </form> 
  ` 
}) 
export class MyFormComponent { 
  form = new FormGroup({ 
    name: new FormControl('') 
  }); 
} 

In this example, the form is a FormGroup object that contains a single FormControl for the name field. The form is bound to the template using the [formGroup] directive, and the name field is bound using the formControlName directive. 

Reactive forms are a powerful and flexible way to build and manage forms in Angular, and they offer many benefits over template-driven forms, such as better separation of concerns, easier unit testing, and improved performance.

Angular 13 brings some thrilling features that Angular developers should be aware of. If you are among people who want to know about the observable updates in the latest version of Angular, here are some updates:  

• View Engine is not available anymore.  
• Changes in the APF (Angular Package Format) are made.  
• IE 11 Support has been removed.  
• TypeScript 4.4 Support is now available.  
• Version 7.4 of RxJS is now available.  
• Angular CLI has been enhanced.  
• Angular Testing has been improved.  
• Dynamic Components have been created.

To update to Angular 12, you need to follow these steps: 

• Make sure you have the latest version of the Angular CLI installed. You can check your version by running ng version, and you can update to the latest version by running npm install -g @angular/cli@latest. 
• Check if there are any breaking changes or updates to the Angular dependencies in your project by running ng update @angular/cli @angular/core. This will check for updates and provide a summary of any breaking changes or updates that are required. 
• If there are any breaking changes or updates, make the necessary changes to your code and fix any issues that are reported by the update tool. 
• Once you have made all the necessary changes, update the Angular dependencies in your project by running ng update @angular/cli @angular/core. This will update the Angular CLI and the core Angular libraries to the latest version. 
• Test your application to make sure everything is working as expected.

In Angular, a provider is a way to configure a service or a value that can be injected into a component, directive, or another service. Providers are defined in the component or module where the service or value is used, and they specify how the service or value should be created or provided. 

There are three types of providers in Angular: 

1. Class providers: A class provider is a provider that creates an instance of a class when the service or value is injected. For example: 

@Injectable() 
export class MyService { 
  // service implementation 
} 
@Component({ 
  providers: [MyService] 
}) 
export class MyComponent { 
  constructor(private myService: MyService) {} 
} 

In this example, the MyService provider is a class provider that creates an instance of the MyService class when it is injected into the MyComponent component. 

Value providers: A value provider is a provider that provides a simple value, such as a string or a number, when the service or value is injected. For example: 

@Component({ 
  providers: [{ provide: 'API_URL', useValue: 'https://api.example.com' }] 
}) 
export class MyComponent { 
  constructor(@Inject('API_URL') private apiUrl: string) {} 
} 

In this example, the API_URL provider is a value provider that provides the string 'https://api.example.com' when it is injected into the MyComponent component. 

2. Factory providers: A factory provider is a provider that creates a service or value by calling a function when the service or value is injected. For example: 

export function createMyService() { 
  return new MyService(); 
} 
@Component({ 
  providers: [{ provide: MyService, useFactory: createMyService }] 
}) 
export class MyComponent { 
  constructor(private myService: MyService) {} 
} 

In this example, the MyService provider is a factory provider that creates an instance of the MyService class by calling the createMyService function when it is injected into the MyComponent component. 

Providers are an important concept in Angular, as they allow you to configure how services and values are created and provided in your application. They are a powerful way to manage dependencies and make your code more modular and reusable

Data binding is the process of connecting a data model to a UI element in such a way that changes to the data model are automatically reflected in the UI element, and vice versa. Data binding is a way to synchronize the data between a data model and a UI element, and it is a key concept in modern UI frameworks such as Angular. 

There are two types of data binding in Angular: 

Interpolation: Interpolation is a one-way data binding technique that allows you to insert the value of a component property into the template HTML. Interpolation is denoted by double curly braces, {{ }}, and it is used to display the value of a property in the template. 

For example: 

<p>Hello, {{ name }}!</p> 

In this example, the name property of the component is bound to the template using interpolation, and the value of the name property is displayed in the template. 

Property binding: Property binding is a one-way data binding technique that allows you to bind the value of a component property to an element property in the template. Property binding is denoted by square brackets, [], and it is used to bind a component property to an element property. 

For example: 

<input type="text" [value]="name"> 

In this example, the value property of the input element is bound to the name property of the component using property binding. 

Data binding is an important concept in Angular, as it allows you to connect the data model to the UI in a declarative way, and it makes it easier to manage and update the data in your application. 

In this Angular Advanced Interview question, students should answer every detail about TypeScript. You can say that- Microsoft-led, Typescript is an open-source programming language. It is a structural superset that includes optional classes, types, and several additional features. It is utilized to create Javascript programs for server-and client-side execution. The Javascript code was written in Typescript and compiled via the typescript compiler. The primary language used to create Angular apps is Typescript, and the syntax to install it globally is as follows: 

npm install -g typescript

Example:- 

function greeter(Name: string) 
{ 
    return "Hai, " + Name; 
} 
let user = "Surya"; 
document.body.innerHTML = greeter(user);

String interpolation is a syntax used for displaying the component data on the HTML template at the end-user. It enables the users to fetch the date from the HTML template file. In addition, it makes changes to the “component.ts” file. It is represented with the double curly braces ({{ }} ).

In Angular, a controller is a JavaScript class that is used to add behavior to a view or a component. Controllers are used in AngularJS, which is an older version of Angular that is now deprecated. 

In AngularJS, controllers are used to define the logic for a view or a component, and they are responsible for handling events, updating the model, and interacting with other services or components. Controllers are defined using the ng-controller directive, and they are associated with a view or a component by specifying the controller name in the directive. 

For example, the following template defines a controller for a component: 

<div ng-controller="MyController"> 
  {{ message }} 
</div> 

In this example, the MyController controller is associated with the div element, and it is responsible for defining the message variable that is displayed in the template. 

Controllers are a feature of AngularJS and are not used in the current version of Angular. In Angular, controllers have been replaced by components, which are classes that define the UI and behavior of a view or a component. Components are more powerful and flexible than controllers, and they provide a better separation of concerns and a more modular and reusable design.

An architectural pattern in software engineering is called MVVM architecture. MVVM stands for Model-View-ViewModel. It is a variant of the common MVC (Model-View-Controller) software design pattern. The primary distinction between the two is that MVC separates the data access logic from the business logic, whereas MVVM separates the data access logic from the business logic. Software programs' development, testing, and maintenance are made simpler by the separation of concerns. 

Data management and storage are the responsibilities of the Model layer in the MVVM architecture. It could be a local data source, a web service, or a database. The view layer handles the data display for the user, which could be a web page, a command-line interface (CLI), or a graphical user interface (GUI). User input is handled by the ViewModel layer, which also updates the View layer, as necessary. It includes the application's business logic. 

Model-View-Presenter (MVP) and Model-View-Controller (MVC) are two software design patterns that are frequently used in conjunction with the MVVM architecture (MVC). Together, these patterns can be leveraged to build an entire software program. 

For modern software applications, the MVVM design is a standard option. It enables programmers to make apps easier to maintain and more responsive. MVVM design can also be used to build simple apps that can be easily ported to many platforms. 

The default module-loading strategy is eager loading, in which, the feature modules under eager loading are loaded before the application starts. In general, it is used for small-size applications. On the other hand, Lazy loading loads the feature modules when there is a demand, making the application faster. It is best for bigger applications where all the modules are not required at the start.

Angular's three fundamental building blocks are Components, modules, and services. Components are the most minor, self-contained units in an Angular application. They are typically used to represent a view or UI element, such as a button or a form input field. Modules are larger units that group one or more related components. Services are singleton objects that provide specific functionality throughout an Angular application, such as data access or logging.

In Angular, one-way data binding is a technique that allows you to bind the value of a component property to an element property in the template, or to interpolate the value of a component property in the template HTML. One-way data binding is a unidirectional process, meaning that changes to the component property are reflected in the UI element, but changes to the UI element are not reflected in the component property. 

One-way data binding is denoted by square brackets, [], and it is used to bind a component property to an element property. 

For example: 

<input type="text" [value]="name"> 

In this example, the value property of the input element is bound to the name property of the component using one-way data binding. 

On the other hand, two-way data binding is a technique that allows you to bind a component property to an element property in such a way that changes to either the component property or the element property are reflected in the other. Two-way data binding is a bidirectional process, meaning that changes to the component property are reflected in the UI element, and changes to the UI element are reflected in the component property. 

Two-way data binding is denoted by square brackets and parentheses, [()], and it is used to bind a component property to an element property. 

For example: 

<input type="text" [(ngModel)]="name"> 

In this example, the ngModel directive is used to bind the value property of the input element to the name property of the component using two-way data binding. 

One-way data binding is a simpler and more efficient technique than two-way data binding, as it only updates the UI element when the component property changes, and it does not require additional logic to manage the flow of data between the component and the UI element. However, two-way data binding can be more convenient in some cases, as it allows you to update the component property and the UI element simultaneously, without having to write additional code. 

The hooks available in AngularJS are as follows:- 

1. ngOnInit() 
2. ngOnChanges(), 
3. ngDoCheck(), 
4. ngAfterContentInit(), 
5. ngAfterContentChecked(), 
6. ngOnDestroy(), 
7. ngAfterViewChecked(), and 
8. ngAfterViewInit(). 

In AngularJS, the $routeProvider is a service that is used to configure the routes for an application. It is typically used in the configuration phase of an AngularJS application, and it is responsible for mapping URLs to views and controllers. 

Here is an example of how you might use the $routeProvider service in an AngularJS application. Lets see how to answer this angular life cycle interview questions: 

angular.module('myApp', ['ngRoute']) 
 .config(function($routeProvider) { 
    $routeProvider 
      .when('/', { 
        templateUrl: 'views/home.html', 
        controller: 'HomeController' 
      }) 
      .when('/about', { 
        templateUrl: 'views/about.html', 
        controller: 'AboutController' 
      }) 
      .otherwise({ 
        redirectTo: '/' 
      }); 
  }); 

In this example, the $routeProvider is being used to configure two routes in the application: one for the root URL (/) and one for the /about URL. For each route, the $routeProvider specifies the template that should be displayed and the controller that should be used to handle the route. If the user navigates to a URL that does not match any of the routes configured with the $routeProvider, the otherwise() method is used to redirect the user back to the root URL. 

It is a lifecycle hook that is usually called after the completion of initializing all date-bound properties of a directive. “ngOnInit ()” is defined as

Interface OnInit 
 { 
   ngOnInit () : void 
} 

In AngularJS, a pipe is a function that takes in data as input and returns a transformed version of that data. Pipes are a useful feature in AngularJS as they allow you to transform data in a declarative way within templates. 

Here is an example of how you might use a pipe in an AngularJS template: 

<p>{{ someText | uppercase }}</p> 

In this example, the uppercase pipe is being used to transform the someText variable to uppercase. The resulting HTML output would be: 

<p>SOME TEXT</p> 

AngularJS comes with a number of built-in pipes, including uppercase, lowercase, and currency. You can also create your own custom pipes if you need to perform more specialized data transformations. 

To use a pipe in an AngularJS template, you place the pipe name after the variable that you want to transform, separated by a vertical bar (|). You can chain multiple pipes together by using multiple vertical bars, like this: 

<p>{{ someText | uppercase | reverse }}</p> 

In this example, the reverse pipe would be applied to the output of the uppercase pipe, resulting in the someText variable being transformed to uppercase and then reversed. 

When we load the page in the browser, the following process takes place: 

• First, the HTML document of the page loads, then the web browser evaluates it. After that, the Javascript file is loaded, and a global object is created. Then, controller functions are executed. Javascript registers those functions. 
• Javascript scans views and apps via HTML. After scanning the view, it is connected to the controller function. 
• AngularJs shows the data handled by the controller and controller functions with a view. Ultimately, the page gets ready.

The process of bootstrapping an Angular application is relatively simple. The following is a step-by-step guide to bootstrapping an Angular application: 

• Create an HTML file and add a div with the attribute "ng-app" and the value of the name of your module. This tells Angular to bootstrap your application using this module. 
• Create a new file called app.js, this file will contain your module. Add the following code to it: 

 var app = angular.module('myApp', []); 

• Add a script tag in your HTML file that references your app.js file. 

<script src="app.js"></script> 

• Create a new file called controller.js, this file will contain your controller. Add the following code to it: 

app.controller('MyController', function($scope) { 
  $scope.message = 'Hello, Angular!'; 
}); 

• Add another script tag in your HTML file that references your controller.js file. 

<script src="controller.js"></script> 

• In your HTML file, add an element with the attribute "ng-controller" and the value of the name of your controller. This tells Angular to use this controller to control the behavior of the elements within it. 

<div ng-controller="MyController"> 
  {{message}} 
</div> 

Finally, you can run your application in any browser, you should see the message "Hello, Angular!" displayed on the page. 

In conclusion, bootstrapping an Angular application is relatively simple. With the use of a ng-app attribute,app.js file and ng-controller attribute, you are able to create a complete Angular program. The angular documentation is a good resource to refer when creating a new angular project.

To break it down in the simplest way, AngularJS initializes automatically upon the DOMContentLoaded event or when the angular.js script is read if, at that time document.readyState is set to 'complete'. At this point, Angular looks for the ng-app directive, which is the root of the AngularJS compilation process. 

• If the ng-app directive is found, then Angular will: 
• Load the module associated with the directive. 
• Create the application injector 
• Start a compilation of DOM from the ng-app directive, the root of the compilation.

The AngularJS Global API is a set of global JavaScript functions for performing common tasks, such as:- 

• Converting Data 
• Iterating Objects 
• Comparing Objects 

AngularJS provides a number of global APIs that you can use in your application. These APIs are accessible from anywhere within your application, and they provide common functionality that you might need. 

Here are some examples of Angular Js global  APIs asked in the angular practical interview questions:  

• angular.module: This API is used to create and retrieve AngularJS modules. 
• angular.element: This API is used to wrap DOM elements as AngularJS elements, which can be used to perform AngularJS actions on the elements. 
• angular.bootstrap: This API is used to manually bootstrap an AngularJS application. 
• angular.copy: This API is used to create a deep copy of an object. 
• angular.equals: This API is used to determine if two objects or values are equal. 
• angular.extend: This API is used to extend the properties of an object with the properties of another object. 
• angular.forEach: This API is used to iterate over an object or an array and perform a function on each item. 

Yes, it is possible to create nested controllers in AngularJS, the example is as follows:-

Example:  

{{msg}} {{name}}! 
Hi {{name}}! 
{{msg}} {{name}}! 
Your name is {{name}}.

ViewEncapsulation recognizes the component styles and shows whether a particular component will affect the entire application. Moreover, it allows users to use the DOM shadow. 

Angular provides three types of ViewEncapsulation that are as follows:- 

• ViewEncapsulation.emulated: The styles in this type are used in other HTML, spread the components. 
• ViewEncapsulation.native: The styles in this type are used in other HTML but do not spread the components. 
• ViewEncapsulation.none: It defines the component style that is visible to all components of the application. 

To understand the angular concepts for interview, you must also know how to use the ng-include. The ng-include directive is used in AngularJS to include an HTML fragment from a separate file in the main HTML template. This can be useful in a number of situations: 

• To break up a large HTML template into smaller, more manageable files. 
• To reuse a common HTML fragment in multiple templates. 
• To conditionally include an HTML fragment based on a condition. 

Here is an example of how you might use the ng-include directive in an AngularJS template: 

<div ng-include="'views/header.html'"></div> 

In this example, the ng-include directive is used to include the contents of the header.html file in the main template. The ng-include directive takes an expression that specifies the URL of the HTML fragment to include. 

You can also use the ng-include directive with variables, like this: 

<div ng-include="templateUrl"></div> 

In this example, the value of the templateUrl variable is used to specify the URL of the HTML fragment to include. This allows you to dynamically specify the HTML fragment to include based on the value of the templateUrl variable. 

Overall, the ng-include directive is a useful tool for including HTML fragments in your AngularJS templates, which can help you to organize and modularize your templates. 

Other than these questions, you may be asked to answer some angular scenario based interview questions. For such questions, you can read about online courses or the provided platforms.  

This question is one of the most common Angular coding questions. Here is how you can answer this -

Yes! Here are the steps to get it done: 

Step 1. Build a new AngularJS project 

1. First and foremost, build a new folder for the project and name it my-angular-project/. 
2. Next, craft an index.html file in the my-angular-project/ folder with a simple AngularJS app inside: 

<!DOCTYPE html> 
<html ng-app="App"> 
  <head> 
    <title>My AngularJS/Flexmonster Project</title> 
    <script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.5.8/angular.js"></script> 
    <script type="text/javascript">angular.module("App", [ ]);</script> 
  </head> 
  <body> 
  </body> 
</html> 

Step 2. Add Flexmonster dependencies 

Add the Flexmonster library to index.html: 

<!DOCTYPE html> 
<html ng-app="App"> 
  <head>  
    <title>My AngularJS/Flexmonster Project</title> 
    <script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.5.8/angular.js"></script> 
    <script type="text/javascript">angular.module("App", [ ]);</script> 
    <script src="https://cdn.flexmonster.com/flexmonster.js"></script>  
  </head> 
  <body> 
  </body> 
</html> 

Step 3. Initialize the pivot table 

Add the flexmonster module to the App and use the fm-pivot directive to add the pivot table to index.html: 

<!DOCTYPE html> 
<html ng-app="App"> 
  <head>   
    <title>My AngularJS/Flexmonster Project</title> 
    <script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.5.8/angular.js"></script> 
    <script type="text/javascript">angular.module("App", ["flexmonster"]);</script> 
    <script src="https://cdn.flexmonster.com/flexmonster.js"></script>  
  </head> 
  <body> 
   <div fm-pivot 
         fm-component-folder="https://cdn.flexmonster.com/"  
         fm-toolbar="true"> 
    </div>  
  </body> 
</html> 

Step 4. Load a sample report 

To see some data on the grid add the fm-report attribute with the report’s URL: 

<!DOCTYPE html> 
<html ng-app="App"> 
  <head>   
    <title>My AngularJS/Flexmonster Project</title> 
    <script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.5.8/angular.js"></script> 
    <script type="text/javascript">angular.module("App", ["flexmonster"]);</script> 
    <script src="https://cdn.flexmonster.com/flexmonster.js"></script>  
  </head> 
  <body> 
   <div fm-pivot 
         fm-component-folder="https://cdn.flexmonster.com/"   
         fm-toolbar="true" 
         fm-report="'https://cdn.flexmonster.com/reports/report.json'"> 
    </div>  
  </body> 
/html>  

A. Simply put, we use Routing in AngularJS when we want to navigate to multiple pages in an application without exiting the single-page application. Users can create different URLs for different content in a single application using AngularJS routes. It is done with the help of ngRoute module, which allows us to access different pages of an application without reloading the entire application. 

Attention: 

• $routeProvider is used to configure the routes. It helps to define what page to display when a user clicks a link. It accepts either when() or otherwise() method. 
• The ngRoute must be added as a dependency in the application module:

Example 1: The below example uses  AngularJS Routing by implementing the “when” method that specifies the new route definition to the $route service. 

<!DOCTYPE html> 
<html> 
<head> 
<script src= 
"https://ajax.googleapis.com/ajax/libs/angularjs/1.6.9/angular.min.js"> 
</script> 
<script src= 
"https://ajax.googleapis.com/ajax/libs/angularjs/1.6.9/angular-route.js"> 
</script> 
</head> 
<body ng-app="myApp"> 
<p> 
<a href="#/!"> 
<img src= 
"https://media.geeksforgeeks.org/wp-content/uploads/20190221234751/geeksforgeeks-logo1.png" 
alt="GeeksforGeeks" 
style="width: 90vw;"> 
</a> 
</p> 
<a href="#!courses">Courses@geeksforgeeks</a> 
<br> 
<a href="#!internships">Internships@geeksforgeeks</a> 
<div ng-view></div> 
<script> 
const app = angular.module("myApp", ["ngRoute"]); 
app.config(function ($routeProvider) { 
$routeProvider 
.when("/", { 
template: `<h1>Welcome to GeeksForGeeks</h1> 
<p> 
Click on the links to change this content 
</p>` 
}) 
.when("/courses", { 
template: `<h1>Courses Offered</h1> 
<p> 
<ul> 
<li>Machine Learning Foundation</li> 
<li>Geeks Classes</li> 
<li>System Design</li> 
</ul> 
</p>` 
}) 
.when("/internships", { 
template: `<h1>Hire With Us</h1> 
<p> 
<ul> 
<li>Software Developer</li> 
<li>Technical Content Writer</li> 
<li>Technical Content Engineer</li> 
</ul> 
</p>` 
}); 
}); 
</script> 
</body> 
</html> 

In AngularJS, a service is a function or object that is available for dependency injection in your application. Services are used to encapsulate and share business logic, models, or data across your application. 

AngularJS comes with a number of built-in services that you can use in your application, such as $http (for making HTTP requests), $timeout (for running functions asynchronously), and $q (for creating and working with promises). ( You can read more about this in the angular programming interview questions) 

You can also create your own custom services in AngularJS. Here is an example of how you might define a custom service in AngularJS: 

angular.module('myApp').service('customService', function() { 
  this.someMethod = function() { 
    // service logic goes here 
  }; 
}); 

In this example, a service called customService is being defined with a single method called someMethod. You can then inject the customService into a controller or other component of your application and use the someMethod method like this: 

angular.module('myApp').controller('MyController', function(customService) { 
  customService.someMethod(); 
}); 

Overall, services are a useful way to encapsulate and share business logic, models, or data across your AngularJS application. They can help you to keep your code organized and avoid duplication of code. 

In AngularJS, routing is the process of mapping URL paths to views and controllers. Routing is useful in AngularJS because it allows you to create a single-page application (SPA) that can navigate between multiple views and controllers without reloading the entire page. 

Here is an example of how you might use routing in an AngularJS application: 

angular.module('myApp', ['ngRoute']) 
  .config(function($routeProvider) { 
    $routeProvider 
      .when('/', { 
        templateUrl: 'views/home.html', 
        controller: 'HomeController' 
      }) 
      .when('/about', { 
        templateUrl: 'views/about.html', 
        controller: 'AboutController' 
      }) 
      .otherwise({ 
        redirectTo: '/' 
      }); 
  }); 

In this example, the $routeProvider service is being used to configure two routes in the application: one for the root URL (/) and one for the /about URL. For each route, the $routeProvider specifies the template that should be displayed and the controller that should be used to handle the route. 

If the user navigates to a URL that does not match any of the routes configured with the $routeProvider, the otherwise() method is used to redirect the user back to the root URL. 

To use routing in an AngularJS application, you need to include the ngRoute module as a dependency of your application and configure the routes using the $routeProvider service.  

You can then use the ng-view directive in your HTML template to specify where the routed views should be displayed. When the user navigates to a different URL, AngularJS will update the ng-view directive with the appropriate view and controller. 

Angular has multiple building blocks with different purposes and goals: 

• Components 
• Modules 
• Directives 
• Decorators 
• Pipes 
• Data Binding 
• Templates 
• Metadata 
• Services 
• Dependency Injection

In AngularJS, a scope is an object that represents the context in which a particular piece of code is executed. Scopes are used to provide separation of concerns in an AngularJS application and to facilitate communication between different parts of the application. 

There are two types of scopes in AngularJS: root scope and child scopes. The root scope is the top-most scope in the scope hierarchy and it is the parent of all other scopes. Child scopes are created whenever a new controller or directive is defined in an AngularJS application. 

Scopes provide a number of important features in AngularJS: 

• They provide a context for expressions to be evaluated in. 
• They provide a way to bind data from the view to the controller. 
• They provide a way to bind data from the controller to the view. 
• They provide a way to share data between controllers. 

Scopes are also used to propagate events between different parts of an AngularJS application. For example, you can use the $emit method of a scope to raise an event that will be propagated up the scope hierarchy, or you can use the $on method to listen for events that are emitted by other scopes. 

Overall, scopes are a fundamental concept in AngularJS and they play a central role in the architecture of an AngularJS application. 

One of the common Angular questions for interview every year, don't miss this one.

In AngularJS, the $rootScope is the top-most scope in the scope hierarchy. It is the parent of all other scopes and it is created by the AngularJS framework when the application is bootstrapped. 

The $rootScope provides a context for expressions to be evaluated in and it is also used to propagate events between different parts of an AngularJS application. You can use the $emit method of the $rootScope to raise an event that will be propagated down the scope hierarchy, or you can use the $on method to listen for events that are emitted by the $rootScope or any of its descendant scopes. 

Here is an example of how you might use the $rootScope in an AngularJS application: 

angular.module('myApp').run(function($rootScope) { 
  $rootScope.someData = 'Hello, world!'; 
}); 

In this example, the someData property is being added to the $rootScope, which makes it available to all other scopes in the application. You can then use the someData property in a template like this: 

<div>{{ someData }}</div> 

The $rootScope is a powerful tool in AngularJS, but you should be careful not to overuse it. It is generally a good idea to avoid adding too much data to the $rootScope and instead use it only for data that needs to be shared across the entire application. 

Connect capability controls the DOM( Archive Article Model ) component utilizing a custom mandate. The link option in the custom directive both registers and updates the DOM. Here are a few types of Link Functions in AngularJS.  

• Scope: – It is a scope object for Angular.  
• Feature: – This customized directive matches the jqLite-wrapped element.  
• Attrs: – It is a hash object with key-valprs consisting of normalized attribute names and their values.  

Each Precise application has a root scope and can have quite a few youngster scopes. When an Angular application is created, the root scope is created, but directives can also create new child scopes. A new child scope is added to the parent scope as a child when it is made. Typically, this tree of child scopes follows the DOM to which they are attached.

There are several essential Building Blocks of Angular, as follows:  

• Modules – Angular maintains modularity. Clearly speaking, Module refers to the file which classifies similar directives, services, directives, and pipes.  
• Components – A component touches on a Javascript class, which, one after another, is furnished as a section in the view.  
• Templates – The component's view is marked out through templates. Templates are primarily the HTML that developers can use on their pages.  
• Metadata – In Angular, Metadata tells a javascript class and how it should be prepared on the screen.  
• Directives – In angular, Directives help the developers to add on the dynamic of the DOM elements. Angular primarily has two kinds of directives – Structural Directives and Attribute Directives.  
• Services - A service is a class that includes any feature, function, or feature with a defined and specific purpose, like handling HTTP requests' side effects.  
• Dependency Injection - We can inject any service or dependency using Dependency Injection, enabling us to provide its instance throughout the entire web application or a specific module or component.  

This is one of the most common Angular advanced interview questions you can expect to come across during Angular interviews.

In AngularJS, you can apply DOM by the following:  

• DOM elements are used to construct documents.  
• DOM elements allow a programmer to navigate the structure of a document.  
• With DOM elements, a programmer can add elements and content.  
• DOM elements permit content and elements to be modified by programmers.

In AngularJS, an expression is a JavaScript-like code snippet that is evaluated by the AngularJS framework. Expressions are used to bind data from the view to the controller and to manipulate values in the view. 

Expressions are similar to JavaScript expressions, but they have a few differences: 

• They do not support control structures (e.g., if statements, for loops). 
• They do not support creating variables or functions. 
• They can only access the properties of the $scope object. 

Expressions are usually used in templates, but they can also be used in controllers, directives, and other parts of an AngularJS application. 

Here is an example of an expression in an AngularJS template: 

<div>{{ someValue + 1 }}</div> 

In this example, the expression someValue + 1 is being evaluated and the result is being inserted into the HTML output. If the value of someValue is 5, the output would be 6. 

Expressions are a useful tool in AngularJS for binding data from the view to the controller and for manipulating values in the view. They are often used in conjunction with directives and controllers to create interactive and dynamic applications. 

AngularJS Routes allow programmers to develop URLs for different content within a web application. The ngRoutes Module allows the developers to access several application pages without reloading the application.  

Important Note: The routes are set up with the help of $routeProvider. Determining which page to display when a user clicks a link is helpful. The when() or otherwise() methods are supported.

In AngularJS, an injector is a service that is responsible for instantiating objects and resolving dependencies. Injectors are used to create and manage the dependencies that are required by an AngularJS application. 

An injector is created whenever an AngularJS application is bootstrapped, and it is used to resolve the dependencies that are needed by the application. When a dependency is needed, the injector looks for an existing instance of the dependency and returns it if it exists. If the dependency does not exist, the injector creates a new instance of the dependency and returns it. 

In AngularJS, you can define dependencies by using the $inject property or the inject function. Here is an example of how you might define dependencies in an AngularJS service: 

angular.module('myApp').service('customService', ['$http', function($http) { 
  this.someMethod = function() { 
    // service logic goes here 
  }; 
}]); 

In this example, the customService service has a dependency on the $http service. The $inject property is used to specify the dependencies that the service has, and the dependencies are then injected into the service's function when the service is instantiated. 

Overall, the injector is a central component of the AngularJS dependency injection system, and it plays a crucial role in the architecture of an AngularJS application. 

In AngularJS, a factory is a function that returns an object. Factories are used to create objects that can be used as dependencies in an AngularJS application. 

Here is an example of a factory in AngularJS: 

angular.module('myApp').factory('customFactory', function() { 
  return { 
    someMethod: function() { 
      // factory logic goes here 
    } 
  }; 
}); 

In this example, the customFactory factory is a function that returns an object with a single method called someMethod. You can then inject the customFactory into a controller or other component of your application and use the someMethod method like this: 

angular.module('myApp').controller('MyController', function(customFactory) { 
  customFactory.someMethod(); 
}); 

Factories are a useful way to encapsulate complex logic and reuse it throughout an AngularJS application. They are often used in conjunction with services and controllers to create modular and reusable components in an AngularJS application. 

Overall, the factory method is a design pattern that is used to create objects in a decoupled and modular way, and it is a central concept in AngularJS. 

You should be ready for any Angular questions for interview and SPA is one such topic.

A single-page application (SPA) is a web application that loads a single HTML page and dynamically updates the page as the user interacts with the application. In a SPA, all the necessary code (HTML, JavaScript, and CSS) is loaded up front, and the application is then able to handle navigation and display views without reloading the entire page. 

AngularJS is a popular framework for building single-page applications because it provides a rich set of features for building client-side applications, including a powerful routing system and a comprehensive set of built-in directives. 

Here is an example of how you might use AngularJS to build a single-page application: 

angular.module('myApp', ['ngRoute']) 
  .config(function($routeProvider) { 
    $routeProvider 
      .when('/', { 
        templateUrl: 'views/home.html', 
        controller: 'HomeController' 
      }) 
      .when('/about', { 
        templateUrl: 'views/about.html', 
        controller: 'AboutController' 
      }) 
      .otherwise({ 
        redirectTo: '/' 
      }); 
  }); 

In this example, the $routeProvider service is being used to configure the routes for the application. When the user navigates to a particular URL, the $routeProvider will display the appropriate template and invoke the corresponding controller. This allows the application to handle navigation and display different views without reloading the entire page. 

Overall, single-page applications are a popular approach to building web applications because they provide a smooth and responsive user experience and can be faster and more efficient than traditional multi-page applications. AngularJS is a powerful framework for building single-page applications, and it is widely used for this purpose.

In AngularJS, the $scope is an object that represents the context in which a particular piece of code is executed. Scopes are used to provide separation of concerns in an AngularJS application and to facilitate communication between different parts of the application. 

Every AngularJS application has at least one root scope, and additional scopes are created whenever a new controller or directive is defined. Scopes provide a number of important features in AngularJS: 

• They provide a context for expressions to be evaluated in. 
• They provide a way to bind data from the view to the controller. 
• They provide a way to bind data from the controller to the view. 
• They provide a way to share data between controllers. 

Scopes are also used to propagate events between different parts of an AngularJS application. For example, you can use the $emit method of a scope to raise an event that will be propagated up the scope hierarchy, or you can use the $on method to listen for events that are emitted by other scopes. 

Overall, the $scope is a fundamental concept in AngularJS and it plays a central role in the architecture of an AngularJS application.

On the other hand, the Integrated Development Environment (IDE) is a program that helps you write flawless code and reduces developers' effort by optimizing the entire development process. It aids in software integration and operating system analysis. The best angular Tools and IDE are: 

• Angular IDE – Precise IDE is profoundly utilized for a quicker and more compelling turn of events. It is an independent plugin that works in conjunction with the Eclipse plugin. Although it was initially used to manage tsconfig.json, it is explicitly designed for Angular.  
• Webstorm – Webstorm, a powerful code editor developed by Jetbrains and IntelliJ, is an excellent choice for coding TypeScript-based Angular 2 applications.  
• Visual Studio Code – Visual Studio Code by Microsoft for Windows, Mac OS X, and Linux. It is a TypeScript-compatible source code editor that supports functions, imported modules, and intelligent code completion based on variable types.  
• Sublime Text – When it comes to code and markup editing, it is a sophisticated option. Nowadays, it is a popular code editor. It has outstanding performance and a user interface that is clean and streamlined.  
• Brackets – It is the best choice for a code editor if you want a perfect blend of visual tools. Brackets is an Angular-based IDE that is both lightweight and extremely powerful. It can be used to create mobile and web applications.  
• Atom – It was developed by GitHub and is favored by users due to its simple installation and accessible environment customization. The Atom TypeScript package can be installed to enhance your TypeScript application experience with Angular apps. APM CLI serves as a built-in package installer as well.  
• Aptana Studio – It is an Angular-specific open-source IDE. It is widely used for JavaScript development and is based on Eclipse. The AngularJS Eclipse extension can be included. It is compatible with numerous other libraries and frameworks. Aptana Studio is available as an Eclipse Plug-in and a stand-alone version.  
• ALM IDE – A cloud-based TypeScript IDE is available from ALM. It removes all barriers to TypeScript use and is simple to use. You can code quickly in TypeScript projects with it. It can be installed easily with just one npm command. On Raspberry, you can even create projects using TypeScript.  

The $watch() function monitors changes to $scope object variables. In most cases, AngularJS will create the $watch() function internally to handle application-wide changes to variables.