Angular, a dynamic and comprehensive open-source web application framework developed by Google, stands at the forefront of modern web development. At its core, Angular embraces a component-based architecture, organizing applications into modular components that encapsulate specific functionalities and user interface elements. Written in TypeScript, a statically-typed superset of JavaScript, Angular not only enhances the readability and maintainability of code but also provides a strong foundation for building scalable and robust single-page applications (SPAs). This combination of modularity and language features empowers developers to create highly responsive and interactive web experiences.

One of Angular’s distinctive features is its commitment to two-way data binding, a mechanism that facilitates seamless synchronization between the application’s data model and the user interface. This bidirectional data flow simplifies development, allowing developers to build dynamic applications with less boilerplate code. Additionally, Angular incorporates a powerful dependency injection system, promoting the creation of loosely coupled, reusable components. This architectural choice enhances code maintainability, encourages code reusability, and facilitates unit testing, contributing to a more efficient and reliable development process.

Explore a comprehensive collection of Angular interview questions and expert answers tailored for experienced developers. Master key concepts, best practices, and advanced techniques to ace your next Angular interview.

Experienced Angular Interview Questions

In Angular, a form is a crucial part of creating interactive user interfaces for collecting and validating user input. Angular provides a powerful and flexible way to work with forms using the Angular Forms module. Angular forms can be either template-driven forms or reactive forms.

Template-driven forms are defined in the HTML template using Angular’s built-in directives, while reactive forms are defined programmatically in the TypeScript component using the FormGroup, FormControl, and FormArray classes.

Here are the basic steps to create a btemplate-driven form in Angular:

Step 1 :

  • Import the FormsModule:In your Angular application, you need to import the FormsModule from the @angular/forms module. You can do this by adding the following import statement in your AppModule or in the component where you want to use the form:
import { FormsModule } from '@angular/forms';

Step 2 :

  • Create the form in the template:In the HTML template of your component, you can define the form using Angular’s form-related directives such as ngForm, ngModel, and form controls like input, select, textarea, etc. For example:
<form #myForm="ngForm" (ngSubmit)="onFormSubmit()">
<label for="name">Name:</label>
<input type="text" id="name" [(ngModel)]="" name="name" required>

<label for="email">Email:</label>
<input type="email" id="email" [(ngModel)]="" name="email" required>

<button type="submit">Submit</button>

Step 3 :

  • Handle form submission :In your component, you can handle the form submission using the ngSubmit event on the form element. You can define a method that will be called when the form is submitted, and you can access the form data using the [(ngModel)] directive, which binds the form controls to properties in your component. For example:
import { Component } from '@angular/core';

selector: 'app-my-form',
template: `
<form (ngSubmit)="onFormSubmit()">
<!-- form controls go here -->
<button type="submit">Submit</button>
export class MyFormComponent {
formData = {
name: '',
email: ''

onFormSubmit() {
// handle form submission logic here
console.log('Form submitted:', this.formData);

Step 4 :

  • Add form validation :Angular provides built-in form validation capabilities such as required, minLength, maxLength, pattern, etc. You can also define custom validation logic using Angular’s Validators API. For example:

These are the basic steps to create a template-driven form in Angular. You can also explore reactive forms, which offer more flexibility and

<form #myForm="ngForm" (ngSubmit)="onFormSubmit()">
<label for="name">Name:</label>
<input type="text" id="name" [(ngModel)]="" name="name" required minlength="3">
<div *ngIf=" &&">
Name is required and must be at least 3 characters.

<label for="email">Email:</label>
<input type="email" id="email" [(ngModel)]="" name="email" required email>
<div *ngIf=" &&">
Email is required and must be a valid email address.

<button type="submit">Submit</button>


  • Angular routing is a feature that allows for building single-pageapplications (SPAs) with multiple views or pages without actually navigating to different URLs. It uses the Angular Router module to define routes and map them to corresponding components.
  • The Angular Router uses a configuration-basedapproach, where routes are defined in the application’s module using the RouterModule and Routes classes. Routes can have parameters, guards, and child routes, and can be used to navigate between different views or pages in the application without triggering a full page reload.
  • Angular provides two ways to work with formstemplate-drivenforms and reactive forms.
  • Template-drivenforms are based on HTML templates and use directives like ngModel for two-way data binding. They are easier to set up and suitable for simple forms with fewer validations. However, they can become complex and hard to manage as the form grows.
  • Reactive forms, on the other hand, are based on explicit creation of form controls and use reactive programming techniques to manage form data. They provide more flexibility and control over form validation and data handling. Reactive forms are suitable for complex forms with complex validationsand dynamic form behavior.
  • Angular services are injectable classes that can be used to share data, logic,and functionality across different parts of an Angular application. They are typically used to encapsulate business logic, data retrieval and manipulation, and communication with external APIs or services.
  • Services are used in Angular to achieve separation of concerns and to follow the principles of single responsibility and modularity. They can be injected into components, directives, or other services using Angular’s dependency injectionmechanism, allowing for easy testing, reusability, and maintainability of code.

There are several ways to optimize performance in Angular applications, including:

  • Using Angular’s change detection strategy wisely to minimize unnecessary change detection cycles.
  • Using lazy loading to load modules and components only when they are needed, reducing the initial loading time.
  • Minimizing DOM manipulation and using the Angular Renderer2 API for efficient rendering.
  • Using trackBy function with ngFor directive to optimize rendering of lists.
  • Optimizing the use of third-partylibraries and plugins to minimize their impact on performance.
  • Properly handling memory leaks and unsubscribing from observables to prevent memory overhead.
  • Using Ahead-of-Time(AOT) compilation to reduce the size of the application and improve load times.

In Angular, every component has a lifecycle. Angular creates and renders these components and also destroys them before removing them from the DOM. This is achieved with the help of lifecycle hooks. Here’s the list of them –

  1. ngOnChanges()
  • Responds when Angular sets/resets data-bound input properties.
  1. ngOnInit()
  • Initialize the directive/component after Angular first displays the data-bound properties and sets the directive/component’s input properties/
  1. ngDoCheck()
  • Detect and act upon changes that Angular can’t or won’t detect on its own.
  1. ngAfterContentInit()
  • Responds after Angular projects external content into the component’s view.
  1. ngAfterContentChecked()
  • Respond after Angular checks the content projected into the component.
  1. ngAfterViewInit()
  • Respond after Angular initializes the component’s views and child views.
  1. ngAfterViewChecked()
  • Respond after Angular checks the component’s views and child views.
  1. ngOnDestroy
  • Cleanup just before Angular destroys the directive/component.

Angular provides an HTTP module that allows you to interact with RESTful APIs and perform HTTP requests to fetch data from a server or send data to a server. The HTTP module in Angular makes it easy to handle asynchronous HTTP operations and handle responses in a structured manner.

Here are the basic steps to use the Angular HTTP module:

  1. Import the HttpClientModule :
  • In your Angular application, you need to import the HttpClientModule from the @angular/common/http module.You can do this by adding the following import statement in your AppModule or in the component where you want to use HTTP:
import { HttpClientModule } from '@angular/common/http';
  1. Inject the HttpClient :
  • In the constructor of your component or service where you want to use HTTP, you need to inject the HttpClient dependency.For example:
import { HttpClient } from '@angular/common/http';

constructor(private http: HttpClient) { }
  1. Use HTTP methods :
  • You can use various HTTP methods provided by the HttpClient to send HTTP requests.Some of the commonly used methods are:
  • GET:To fetch data from a server. For example:
this.http.get('').subscribe(data => {

POST: To send data to a server. For example:

const data = { name: 'John', age: 30 };'', data).subscribe(response => {

PUT: To update data on a server. For example:

const data = { name: 'John', age: 30 };
this.http.put('', data).subscribe(response => {

DELETE: To delete data from a server. For example:

this.http.delete('').subscribe(response => {
  1. Handle responses :
  • You can handle the responses from HTTP requests using the subscribe method, which allows you to subscribe to the observable returned by the HTTP methods. You can also use RxJS operators to map, filter, or transform the data received from the server.
  1. Handle errors :
  • You can handle errors that may occur during HTTP requests using the catchError operator from RxJS. For example:
import { catchError } from 'rxjs/operators';

catchError(error => {
return throwError('An error occurred. Please try again later.');
).subscribe(data => {

These are the basic steps to use the Angular HTTP module to perform HTTP requests in your Angular application. You can refer to the official Angular documentation for more advanced usage and configuration options.

Angular is a JavaScript framework that allows you to build dynamic web applications. It uses TypeScript as its primary programming language, which is a typed superset of JavaScript. TypeScript provides additional data types that can be used in Angular applications to specify the type of data being used or passed around in the application. Some commonly used data types in Angular include:

  1. string:
  • Represents a string of characters, such as a text or a URL.
const name: string = 'John';
  1. number:
  • Represents numeric values, including integers and floating-point numbers.
const age: number = 30;
const salary: number = 50000.50;
  1. boolean:
  • Represents boolean values, either true or false.
const isStudent: boolean = false;
  1. any:
  • Represents a value of any type, allowing for dynamic typing. Use with caution, as it bypasses TypeScript’s static typing checks.
const dynamicValue: any = 'Some dynamic value';
  1. Array:
  • Represents an array of values of a specific type.
const numbers: number[] = [1, 2, 3, 4, 5];
const names: string[] = ['John', 'Jane', 'Jack'];
  1. Object:
  • Represents an object with key-value pairs. You can define the structure of the object using TypeScript interfaces or classes.
interface User {
name: string;
age: number;

const user: User = {
name: 'John',
age: 30
  1. enum:
  • Represents a set of named values.
enum Gender {
Male = 'male',
Female = 'female',
Other = 'other'

const gender: Gender = Gender.Male;

These are some of the commonly used data types in Angular applications. TypeScript provides many other data types, such as tuples, unions, and intersections, which can be used for more advanced data manipulation and type checking in Angular projects.

Error handling is an important aspect of developing Angular applications to ensure that the application is robust and can handle errors gracefully. Angular provides several ways to handle errors in different parts of an application. Here are some common approaches for error handling in Angular:

  1. Error handling in HTTP requests :
  • You can use the catchError operator from RxJS to handle errors that may occur during HTTP requests. For example:
import { catchError } from 'rxjs/operators';
import { throwError } from 'rxjs';

catchError(error => {
return throwError('An error occurred. Please try again later.');
).subscribe(data => {
  1. Error handling in Angular services :
  • If you have custom services in your Angular application, you can handle errors within the service methods themselves. For example:
import { Injectable } from '@angular/core';
import { HttpClient } from '@angular/common/http';
import { throwError } from 'rxjs';
import { catchError } from 'rxjs/operators';

export class DataService {

constructor(private http: HttpClient) { }

getData() {
return this.http.get('').pipe(
catchError(error => {
return throwError('An error occurred. Please try again later.');
  1. Global error handling using Angular ErrorHandler :
  • Angular provides an ErrorHandler class that you can extend to create a global errorhandler for your application. You can implement this handler to capture and handle any unhandled errors that may occur during runtime. For example:
import { ErrorHandler } from '@angular/core';

export class GlobalErrorHandler implements ErrorHandler {
handleError(error: any): void {
console.error('An error occurred:', error);
// Perform custom error handling logic here

// In your AppModule:
import { NgModule, ErrorHandler } from '@angular/core';
import { GlobalErrorHandler } from './global-error-handler';

// ...
providers: [
{ provide: ErrorHandler, useClass: GlobalErrorHandler }
export class AppModule { }
  1. Displaying error messages to users :
  • You can also display error messages to users in your Angular application, such as showing error messages in the UI or using notification libraries. Angular provides built-inerror handling mechanisms, such as Angular forms‘ error handling and template-driven or reactive form validation, to display validation errors to users.

These are some of the common approaches for error handling in Angular applications. It’s important to choose the right approach based on your specific use case and application requirements. Additionally, logging errors to a centralized logging service can also be beneficial for troubleshooting and debugging purposes.


MVVM stands for Model-View-ViewModel, and it is a software architectural pattern that is commonly used in the development of graphical user interfaces (GUIs) for applications, especially in the context of modern software development frameworks like WPF (Windows Presentation Foundation) and Xamarin.

In MVVM, the software is divided into three main components:

Model :

  • The Model represents the data and business logic of the application. It encapsulates the data, provides methods for accessing and manipulatingthe data, and handles business logic such as validation, computation, and data retrieval.

View :

  • The View is the user interface (UI) of the application. It is responsible for displaying the data to the user and capturing user input. The View defines the layout, appearance,and behavior of the user interface.

ViewModel :

  • The ViewModel acts as an intermediary between the Model and the View. It provides the data and commands that are required by the View to displaythe data and handle user input. The ViewModel exposes data properties and commands that the View binds to, and it also communicates with the Model to retrieve and update the data. The ViewModel also implements logic for handling user input and performing operations based on the business logic defined in the Model.

The key idea behind MVVM is the separation of concerns, where each component has a specific role and responsibility. The Model is responsible for encapsulating the data and business logic, the View is responsible for displaying the data and capturing user input, and the ViewModel acts as a bridge between the Model and the View, providing the necessary data and commands for the View to operate on.

One of the key advantages of MVVM is its support for data binding, which allows for automatic synchronization of data between the Model and the View. When data in the Model changes, it automatically updates the View, and when the user interacts with the View, the ViewModel automatically updates the Model. This helps in creating a decoupled, maintainable, and testable codebase.

Overall, MVVM is a popular architectural pattern that provides a clear separation of concerns, promotes code reusability, and improves the maintainability and testability of software applications with graphical user interfaces.

The FormBuilder is a syntactic sugar that speeds up the creation of FormControl, FormGroup, and FormArray objects. It cuts down on the amount of boilerplate code required to create complex forms.

When dealing with several forms, manually creating multiple form control instances can get tedious. The FormBuilder service provides easy-to-use control generation methods.

Follow the steps below to use the FormBuilder service:

  • Import the FormBuilder class to your project.
  • FormBuilder service should be injected.
  • Create the contents of the form.

To import the FormBuilder into your project use the following command in the typescript file:

import { FormBuilder } from '@angular/forms';


Every Angular application consists of components and templates that the browser cannot understand. Therefore, all the Angular applications need to be compiled first before running inside the browser.

Angular provides two types of compilation:

  • JIT(Just-in-Time) compilation
  • AOT(Ahead-of-Time) compilation

In JIT compilation, the application compiles inside the browser during runtime. Whereas in the AOT compilation, the application compiles during the build time.

The advantages of using AOT compilation are:

  • Since the application compiles before running inside the browser, the browser loads the executable codeand renders the application immediately, which leads to faster rendering.
  • In AOT compilation, the compiler sends the external HTML and CSS files along with the application, eliminating separate AJAX requests for those source files, which leads to fewer ajax requests.
  • Developers can detect and handle errors during the building phase, which helps in minimizing errors.
  • The AOT compiler adds HTML and templates into the JS files before they run inside the browser. Due to this, there are no extra HTML files to be read, which provide better securityto the application.

By default, angular builds and serves the application using JIT compiler:

ng build
ng serve

For using AOT compiler following changes should be made:

ng build --aot
ng serve --aot


In Angular, we use two different kinds of compilers:

  • Just-in-time(JIT) compiler
  • Ahead-of-time(AOT) compiler

Both these compilers are useful but for quite different purposes. The JIT compiler is used to compile TypeScript to JavaScript as our browsers cannot understand TypeScript but only JavaScript. This compilation step is done in a development environment, i.e., when less time is needed to be spent on compilation and more in development to quickly iterate over features. The JIT compiler is used when we use ng serve or ng build command to serve the app locally or create an uncompressed build of the entire codebase.

On the other hand, the AOT compiler is used to create a minified production build of the entire codebase, which can be used in production. To use the AOT compiler, we have to use the ng build command with the –prod blog: ng build –prod. This instructs the Angular CLI to create an optimized production build of the codebase. This takes a bit more time because several optimizations such as minification can take time, but for production builds, this time can be spared.

  1. Components :
  • A component is simply a directive with a template. It is used to define a single piece of the user interface using TypeScript code, CSS styles,and the HTML template. When we define a component, we use the component decorated with the @ symbol and pass in an object with a selector attribute. The selector attribute gives the Angular compiler the HTML tag that the component is associated with so that, now, when it encounters this tag in HTML, it knows to replace it with the component template.
  1. Structural :
  • Structural directives are used to change the structure of a view. For example, if we wish to show or hide some data based on some property, we can do so by using the ngIf directive,or if we wish to add a list of data in the markup, we can use *ngFor, and so on. These directives are called structural directives because they change the structure of the template.
  1. Attribute :
  • Attribute directives change the appearance or behavior of an element, component, or another directive.They are used as the attributes of elements. Directives such as ngClass and ngStyle are attribute directives.
  1. Components :
  • A component can control numerous views wherein each of the views is a particular part on the screen. All Angular applications have a minimum of one component called the root component. This component is bootstrappedin the root module, the main module. All the components include the logic of the application that is defined in a class, while the main role of the class is to interact with the view using an API of functions and properties.
  1. Data binding :
  • Data binding is the process in which the various sectionsof a template interact with the component. The binding markup needs to be added to the HTML template so that Angular can understand how it can connect with the component and template.
  1. Dependency
  • injection: It uses DI so that it can offer the necessary dependencies, mainly services,to the new components. The constructor parameters of a component inform Angular regarding the numerous services needed by the component, and DI provides a solution that gives the necessary dependencies to the new class
  1. Directives :
  • Angular templates are of dynamic nature,and directives help Angular understand how it can transform the DOM while manifesting the template.
  1. Metadata :
  • Classes have metadata attachedto them with the help of decorators so that Angular will have an idea of processing the class.
  1. Modules :
  • Module or NgModuleis a block of code organized using the necessary capabilities set, having one specific workflow. All Angular applications have at least one module, the root module, and most of the applications have numerous modules.
  1. Routing :
  • Angular router helps interpret the URLof a browser to get a client-generated experience and view. This router is bound to page links so that Angular can go to the application view as soon as the user clicks on it.
  1. Services :
  • Service is a vast category that ranges from functions and values to features that play a significant rolein Angular applications.
  1. Template :
  • The view of each component is linked with a template, and an Angular template is a type of HTML tagthat allows Angular to get an idea of how it needs to render the component.

The ngFor directive is a structural directive in Angular, a popular JavaScript framework for building web applications, that is used for iterating over collections and creating repeated content dynamically in Angular templates. Its main purpose is to generate and render HTML elements or Angular components for each item in a collection, such as an array or an object.

The primary use case of the ngFor directive is to render a list of items in an Angular template. It provides an easy and declarative way to iterate over an array or object, and dynamically create UI elements, such as HTML elements or Angular components, based on the data in the collection.

Here are some key purposes of the ngFor directive:

  1. Iterating over collections :
  • The ngFor directive allows developers to loop over collections,such as arrays or objects, and generate content based on the items in the collection. This is useful for displaying lists of items, such as a list of products, a list of users, or a list of posts, dynamically in the UI.
  1. Dynamic content generation :
  • With ngFor, developers can dynamically generate content based on the data in the collection. This can include creating HTML elements, Angular components,or other custom UI components, for each item in the collection. This allows for dynamic rendering of content based on changing data.
  1. Templating and rendering logic :
  • ngForprovides a powerful way to define the template and rendering logic for each item in the  It supports various template features, such as conditional rendering, data binding, and event binding, which allows for customization and flexibility in rendering the repeated content.
  1. Track by feature :
  • ngFor provides a trackByfeature that allows developers to optimize performance when iterating over large collections by providing a unique identifier for each item in the collection. This can help Angular to efficiently track and update the DOM elements associated with the repeated content, resulting in better performance.

In summary, the ngFor directive in Angular is used for iterating over collections and dynamically generating content in Angular templates. It provides flexibility, customization, and performance optimizations for rendering repeated content based on data in Angular applications.

The ngIf directive is a structural directive in Angular, a popular JavaScript framework for building web applications, that is used for conditionally rendering content in Angular templates. Its main purpose is to conditionally show or hide content based on a boolean expression or a truthy/falsy value in the Angular component’s context.

The primary use case of the ngIf directive is to conditionally render content in the UI based on certain conditions. It allows developers to control the visibility of content in the template dynamically, based on the state or properties of the Angular component or its associated data.

Here are some key purposes of the ngIf directive:

  1. Conditional rendering :
  • The ngIf directive allows developers to conditionally render content in the UI based on a boolean expression or a truthy/falsy value in the component’s context.This is useful for showing or hiding elements, such as HTML elements or Angular components, based on the value of a variable, the result of an expression, or the state of the application.
  1. Dynamic content :
  • With ngIf, developers can dynamically generatecontent in the template based on the conditions specified. This can include rendering different parts of the UI, showing or hiding specific sections, or changing the content displayed based on user interactions or other events.
  1. Performance optimization :
  • ngIf can help optimize performance by conditionally rendering content only when it is needed. If the condition specified in the ngIf directive evaluates to false,the associated content will not be rendered in the DOM, reducing unnecessary rendering and improving performance.
  1. Simplified UI logic:
  • ngIf allows developers to encapsulate complex UI logic and conditional rendering in the template,making the code more maintainable and readable. It provides a clean and declarative way to express conditional rendering logic without cluttering the component code with complex conditionals.

In summary, the ngIf directive in Angular is used for conditionally rendering content in Angular templates based on boolean expressions or truthy/falsy values. It provides flexibility, performance optimization, and simplified UI logic for dynamically controlling the visibility of content in Angular applications.

In Angular, constructor and ngOnInit are two different concepts related to component lifecycle hooks.

In summary, constructor is a standard TypeScript class constructor that is called during the instantiation of a component, while ngOnInit is a lifecycle hook in Angular that is called after the component has been fully initialized. They have different timing and use cases, with ngOnInit being the recommended place for performing component initialization tasks.

  1. constructor :
  • The constructor is a standard TypeScript class constructor that gets called when an instance of a component is created. It is a basic part of the class instantiation process and is used to initialize the component’s properties,set up dependencies, and perform other tasks that need to be done when an object is created. However, at the time the constructor is called, the component’s view and child components are not yet initialized, and the component has not yet been rendered in the DOM.
  1. ngOnInit :
  • ngOnInit is a lifecycle hookin Angular that is called after the component has been created and the component’s view and child components have been  It is a part of the Angular component lifecycle and is typically used for performing initialization tasks that need access to the component’s view and child components. It is commonly used for tasks such as making API calls, initializing component properties, setting up subscriptions, or performing other tasks that require the component to be fully initialized.

Here are some key differences between constructor and ngOnInit:

  1. Timing :
  • The constructor is called during the instantiation of a component, while ngOnInit is called after the component has been fully initializedand its view and child components have been initialized. This means that ngOnInit is the appropriate place for tasks that require access to the component’s view and child components.
  1. Use cases :
  • The constructor is typically used for basic object initialization and setup, while ngOnInit is used for more complex tasks that require the component to be fully initialized. ngOnInit is commonly used for tasks such as making API calls,initializing component properties, setting up subscriptions, or performing other tasks that need to interact with the component’s view or child components.
  1. Best practices:
  • In general, it is recommended to use ngOnInit for performing component initialization tasks,as it ensures that the component’s view and child components are fully initialized before the tasks are executed. Using ngOnInit also helps to follow Angular’s component lifecycle and separation of concerns principles.
  • An Angular application is a Single Page Application,or SPA. This means that the entire application lives within a single page, and all of the resources (HTML, CSS, JavaScript, etc.) are loaded when the page is first loaded. Angular uses the Model-View-Controller, or MVC, architecture pattern to manage its data and views. The Model is the data that the application uses, the View is what the user sees, and the Controller is responsible for managing communication between the Model and the View.
  • When a user interacts with an Angular application, the Angular framework will automaticallyupdate the View to reflect any changes in the data. This means that Angular applications are very responsive and fast, as the user does not need to wait for the page to reload in order to see updated data.
  • Angular applications are also very scalable, as they can be divided into small modulesthat can be loaded independently of each other. This means that an Angular application can be easily extended with new functionality without having to rewrite the entire application.
  • Overall, Angular applications are very fast, responsive,and scalable. They are easy to develop and extend, and provide a great user experience.

The following is is an example of coding from an angular.json file:

"build": {

"builder": "@angular-devkit/build-angular:browser",

"options": {

"outputPath": "dist/angular-starter",

"index": "src/index.html",

"main": "src/main.ts",

"polyfills": "src/polyfills.ts",

"tsConfig": "",

"aot": false,

"assets": [




"styles": [







  • Components, modules and services are the three fundamental building blocks in Angular. Components are the smallest, self-containedunits in an Angular application. They are typically used to represent a view or UI element, such as a button or a form input field.

Code example:

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


selector: 'app-test',

templateUrl: './test.component.html',

styleUrls: ['./test.component.css']


export lass TestComponent implements OnInit {

constructor() {}

ngOnInit() {


  • Modules are larger units that group together one or more related components. Servicesare singleton objects that provide specific functionality throughout an Angular application, such as data access or 

Code example:

import { BrowserModule } from '@angular/platform-browser';

import { NgModule } from '@angular/core';

import { AppComponent } from './app.component';

import { TestComponent } from './test/text.component';


declarations: [




imports: [



providers: [],

bootstrap: [AppComponent]


export class AppModule { }

Each component in Angular has its own isolated scope. This means that a component’s dependencies (services, other components, etc.) are not accessible to any other component outside of its own scope. This isolation is important for ensuring modularity and flexibility in an Angular application.

  • Each component in Angular has its own isolated scope.This means that a component’s dependencies (services, other components, etc.) are not accessible to any other component outside of its own scope. This isolation is important for ensuring modularity and flexibility in an Angular application.

Code example:

import { Injectable } from '@angular/core';


providedIn: 'root'


export class TestServiceService {

constructor() { }


When designing an Angular application, it is important to keep these three building blocks in mind. Components should be small and self-contained, modules should group together related components, and services should provide shared functionality across the entire app. By following this design principle, you can create an Angular application that is modular, flexible, and easy to maintain.


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