Top 200 Angular Interview Questions and Answers 2024

Data binding in Angular is a way to establish a connection between the UI and the application's data.

• Data binding allows automatic synchronization of data between the model and the view.

• It eliminates the need for manual DOM manipulation.

• There are different types of data binding in Angular, such as interpolation, property binding, event binding, and two-way binding.

• Interpolation: {{ data }}

• Property binding: [property]='data'

• Event binding: (event)='handler()'

• Two-way binding: [(...read more

Angular has four types of data bindings: Interpolation, Property binding, Event binding, and Two-way binding.

• Interpolation: {{ expression }}

• Property binding: [property]="expression"

• Event binding: (event)="expression"

• Two-way binding: [(ngModel)]="expression"

JavaScript is a programming language used for web development, while Angular is a JavaScript framework for building web applications.

• JavaScript is a programming language that allows developers to add interactivity and dynamic features to websites.

• Angular is a JavaScript framework that provides a structure for building web applications.

• JavaScript can be used independently to create web functionality, while Angular is built on top of JavaScript and provides additional features ...read more

Angular is a complete framework while React is a library for building UI components.

• Angular is a complete framework with built-in features like routing, forms, and animations.

• React is a library for building UI components and requires additional libraries for features like routing and forms.

• Angular uses two-way data binding while React uses one-way data flow.

• Angular has a steeper learning curve while React is easier to learn.

• Angular is maintained by Google while React is maint...read more

loadChildren is used to lazy load modules in Angular

• Used in routing to load modules on demand

• Improves initial load time of the application

• Syntax: loadChildren: () => import('path/to/module').then(m => m.ModuleName)

AngularJS and Angular are JavaScript frameworks used for building web applications.

• AngularJS is an older version of Angular, released in 2010.

• Angular is a complete rewrite of AngularJS, released in 2016.

• Angular uses TypeScript, a superset of JavaScript, while AngularJS uses plain JavaScript.

• Both frameworks use a component-based architecture and have a strong focus on dependency injection.

• Angular has a more streamlined and efficient performance compared to AngularJS.

To call REST APIs in Angular, use the HttpClient module and its methods like get(), post(), put(), delete().

• Import the HttpClientModule in your Angular module

• Inject the HttpClient service in your component or service

• Use the HttpClient methods to make HTTP requests to the REST APIs

• Handle the response using observables and subscribe to them

• Example: httpClient.get('https://api.example.com/data')

• Example: httpClient.post('https://api.example.com/data', postData)

Pure pipes are stateless and only depend on input data, while impure pipes have internal state and can have side effects.

• Pure pipes are faster and more efficient than impure pipes.

• Pure pipes are used for simple transformations of data, while impure pipes are used for more complex transformations.

• Examples of pure pipes include currency and date formatting, while examples of impure pipes include filtering and sorting.

• To mark a pipe as pure, add the @Pipe({pure: true}) decorator...read more

Angular pipe is a feature that allows transforming data before displaying it in the view.

• Pipes are used to format, filter, and transform data.

• They can be used in interpolation, property binding, and directive binding.

• Built-in pipes include DatePipe, UpperCasePipe, and CurrencyPipe.

• Custom pipes can be created using the @Pipe decorator.

Business logic, presentation logic, and service logic can be separated using Angular's component architecture.

• Create separate components for each logic layer

• Use services to handle business logic

• Use pipes for presentation logic

• Keep components simple and focused on one task

• Use dependency injection to share services between components

A component is a building block of an Angular application that represents a part of the UI.

• Components are reusable and self-contained

• They have a template that defines the view

• They have a class that defines the behavior

• They can communicate with other components using @Input and @Output decorators

Pure pipes are stateless and only depend on input values, while impure pipes can have side effects and depend on external factors.

• Pure pipes are faster and more efficient than impure pipes.

• Pure pipes are used for simple transformations of data, while impure pipes are used for more complex transformations.

• Pure pipes can be memoized for better performance.

• Impure pipes can cause performance issues if not used carefully.

• Examples of pure pipes include currency and date formatting,...read more

Angular life cycle is a series of events that occur from the creation of a component to its destruction.

• ngOnChanges - called when an input property changes

• ngOnInit - called once after the first ngOnChanges

• ngDoCheck - called during every change detection cycle

• ngAfterContentInit - called after content is projected into component

• ngAfterContentChecked - called after every check of projected content

• ngAfterViewInit - called after component's view has been initialized

• ngAfterViewChec...read more

Components in Angular can communicate with each other using @Input, @Output, and services.

• Use @Input to pass data from parent to child component

• Use @Output to emit events from child to parent component

• Use services to share data between components that are not directly related

• Use RxJS subjects to create a shared data stream between components

ngModel is a directive in AngularJS that binds the value of HTML controls to application data.

• ngModel is used for two-way data binding in AngularJS.

• It can be used with input, select, textarea, and custom form controls.

• Example:

Decorators and directives are features in programming languages that allow for the modification or extension of code behavior.

• Decorators are used in languages like Python to modify the behavior of functions or classes.

• Directives are used in AngularJS to add behavior to HTML elements.

• Decorators in Python are denoted by the @ symbol, like @staticmethod.

• Directives in AngularJS are denoted by attributes in HTML tags, like ng-model.

Angular Routes are used to navigate between different components and views in an Angular application.

• Routes are defined in the app-routing.module.ts file

• Each route maps a URL path to a component

• Routes can have parameters and child routes

• Navigation between routes can be done using routerLink directive or programmatically using Router service

Angular is a JavaScript framework for building web applications with a modular architecture.

• Angular uses a component-based architecture to build reusable UI components

• It uses a declarative approach to define UI elements and their behavior

• Angular provides a powerful set of tools for data binding, dependency injection, and routing

• It follows the MVC (Model-View-Controller) pattern to separate concerns and improve maintainability

• Angular also supports server-side rendering for bet...read more

Angular life cycle hooks are methods that allow you to tap into specific points in a component's life cycle.

• ngOnChanges: called when an input property changes

• ngOnInit: called once after the first ngOnChanges

• ngDoCheck: called during every change detection run

• ngAfterContentInit: called after content is projected into the component

• ngAfterContentChecked: called after every check of projected content

• ngAfterViewInit: called after the component's view has been initialized

• ngAfterView...read more

Template driven forms are based on directives while reactive forms are based on reactive programming.

• Template driven forms are easier to use and require less code.

• Reactive forms are more flexible and allow for more complex validation.

• Template driven forms are suitable for simple forms while reactive forms are better for complex forms.

• Template driven forms use two-way data binding while reactive forms use observable streams.

• Template driven forms are synchronous while reactive ...read more

Building blocks in Angular are components, directives, services, and modules.

• Components are the basic building blocks of Angular applications.

• Directives add behavior to an existing DOM element or component.

• Services are used to share data or logic across components.

• Modules are used to organize the application into cohesive blocks of functionality.

Angular hooks or lifecycle are methods that allow developers to tap into key moments in a component's lifecycle.

• Angular components have several lifecycle hooks such as ngOnInit, ngOnChanges, ngDoCheck, ngOnDestroy, etc.

• These hooks allow developers to perform actions at specific points in a component's lifecycle, such as initialization, change detection, and destruction.

• For example, ngOnInit is used to initialize data in a component when it is first created, while ngOnDestroy ...read more

Angular directives are markers on a DOM element that tell AngularJS to attach a specified behavior to that DOM element.

• Directives are used to create custom HTML tags that serve as new, reusable widgets.

• They can be used to manipulate the DOM, add event listeners, and create reusable components.

• Some built-in directives include ng-model, ng-repeat, and ng-show.

• Directives can be restricted to only apply to certain types of elements, such as attributes or elements.

• They can also be...read more

ng-content is a directive in Angular that allows for dynamic insertion of content.

• It is used to project content into a component from the outside.

• It is often used in combination with ng-template and ng-container.

• It can be used to create reusable components that can be customized with different content.

• It is useful for creating layouts and templates that can be reused across multiple components.

ngFor is a directive in Angular used for iterating over a collection of data and rendering it in the UI.

• ngFor is used in Angular templates to display a list of items by iterating over an array or object.

• It is commonly used with an *ngFor directive in HTML templates.

• Example:

  {{item}}

Use Angular's 'resolve' property to load component after services are loaded.

• Create a resolver service that waits for all three services to complete before resolving.

• Add the resolver service to the 'resolve' property of the component's route.

• Access the resolved data in the component using the ActivatedRoute service.

• Example: { path: 'my-component', component: MyComponent, resolve: { data: MyResolverService } }

NgOnInit is a lifecycle hook in Angular that is called after the component has been initialized, while the constructor is a TypeScript feature used to initialize class properties.

• NgOnInit is specific to Angular components, while constructor is a general TypeScript feature.

• NgOnInit is used for initialization logic that relies on Angular's view and input bindings being initialized, while constructor is used for basic initialization of class properties.

• NgOnInit is called after A...read more

I have extensive experience in both Java and Angular.

• I have worked on multiple projects using Java and Angular.

• I am proficient in developing web applications using Angular.

• I have experience in developing RESTful web services using Java.

• I have worked with various Java frameworks such as Spring and Hibernate.

• I have experience in using Angular Material for UI development.

• I have knowledge of TypeScript and JavaScript.

• I have experience in using Git for version control.

Angular is a front-end framework for building client-side applications, while Node.js is a back-end runtime environment for running server-side applications.

• Angular is used for building dynamic web applications with HTML, CSS, and TypeScript.

• Node.js is used for server-side scripting and building scalable network applications.

• Angular is a front-end framework developed and maintained by Google.

• Node.js is a back-end runtime environment that uses JavaScript on the server side.

• Ang...read more

Angular is a front-end framework developed by Google, while React is a JavaScript library for building user interfaces.

• Angular is a full-fledged front-end framework with its own ecosystem, while React is a JavaScript library focused on building UI components.

• Angular uses TypeScript, while React uses JavaScript.

• Angular has a two-way data binding feature, while React uses a one-way data flow.

• Angular has a steep learning curve due to its complexity, while React is easier to lear...read more

Implement security in Angular by using built-in features like Angular Router Guards, HTTP Interceptors, and secure coding practices.

• Use Angular Router Guards to control access to routes based on user authentication and authorization.

• Implement HTTP Interceptors to intercept and modify HTTP requests and responses for adding security headers or handling authentication tokens.

• Follow secure coding practices like input validation, output encoding, and avoiding client-side data mani...read more

Angular is a JavaScript framework for building web applications. TypeScript is a superset of JavaScript that adds static typing.

• Angular is a popular frontend framework developed by Google.

• It uses TypeScript as its primary language.

• TypeScript is a superset of JavaScript that adds optional static typing and other features.

• It helps catch errors at compile time and improves code maintainability.

• TypeScript code is compiled into JavaScript code that can run in any browser.

• Angular u...read more

Optimizing an Angular project involves reducing bundle size, lazy loading modules, using AOT compilation, and optimizing performance.

• Reduce bundle size by removing unused code and dependencies

• Lazy load modules to only load components when needed

• Use Ahead-of-Time (AOT) compilation for faster rendering

• Optimize performance by minimizing DOM manipulation and using trackBy in ngFor loops

The design pattern commonly used in Angular is the Observer pattern.

• The Observer pattern is used to establish a one-to-many dependency between objects.

• In Angular, Observables are used to implement the Observer pattern for handling asynchronous data streams.

• Components in Angular often use Observables to subscribe to changes and react accordingly.

Angular is a popular front-end framework for building dynamic web applications.

• Angular is developed and maintained by Google.

• It uses TypeScript for building web applications.

• Advantages include two-way data binding, dependency injection, and modular architecture.

• Angular provides a rich set of built-in directives and components for faster development.

• It has a large community and ecosystem for support and resources.

A module in Angular is defined using the NgModule decorator.

• Import the NgModule decorator from @angular/core

• Use the decorator to define the module and its properties

• Export the module to make it available for other modules to import

Angular is a JavaScript framework for building web applications.

• Uses TypeScript for building scalable and maintainable applications

• Provides two-way data binding for easy synchronization between model and view

• Offers a powerful set of built-in directives and services for faster development

• Supports modular architecture and dependency injection for better code organization

• Enables easy integration with other libraries and frameworks

• Example: Angular is used by Google, Microsoft, an...read more

React JS is a lightweight library for building user interfaces, while Angular is a full-fledged framework with more features.

• React is more flexible and allows for easier integration with other libraries and frameworks.

• Angular provides more out-of-the-box features like routing, forms, and HTTP client.

• React uses a virtual DOM for better performance, while Angular uses two-way data binding for easier data manipulation.

• React is maintained by Facebook, while Angular is maintained ...read more

To create a service in Angular, you can use the 'ng generate service' command or manually create a service file.

• Use the Angular CLI command 'ng generate service serviceName' to create a new service file

• Manually create a service file by creating a new TypeScript file with the '.service.ts' extension

• Inject the service into components or other services by adding it to the providers array in the @Injectable decorator

• Define methods and properties in the service class to provide fu...read more

Routing in MVC and Angular is the mechanism of mapping URLs to controller actions or components.

• In MVC, routing is used to define the URL patterns and map them to specific controller actions.

• In Angular, routing is used to navigate between different components based on the URL.

• Routing in MVC is typically configured in the RouteConfig class, while in Angular it is configured in the RouterModule.

• Example in MVC: routes.MapRoute('Default', '{controller}/{action}/{id}', new { contr...read more

To call an API in Angular, use HttpClient module to make HTTP requests.

• Import HttpClientModule in app.module.ts

• Inject HttpClient in the component/service where API call needs to be made

• Use HttpClient methods like get(), post(), put(), delete() to make API calls

• Subscribe to the Observable returned by HttpClient methods to handle the response

Life cycle hooks are functions that allow you to tap into the lifecycle of Angular components.

• Life cycle hooks are predefined methods that get called at specific points in the component's life cycle.

• They allow you to perform actions like initialization, change detection, and destruction.

• Examples of life cycle hooks include ngOnInit, ngOnChanges, and ngOnDestroy.

The application would not work properly without @NgModule as it is required to bootstrap the application and configure dependencies.

• Without @NgModule, the application would not be able to bootstrap and start properly.

• NgModule is used to configure dependencies, such as components, directives, and services.

• NgModule also helps in organizing the application into modules for better maintainability and reusability.

Server-side rendering (SSR) in Angular can be enabled by using Angular Universal.

• Install Angular Universal using Angular CLI

• Create a new Angular Universal project

• Update app.module.ts to include server-side rendering

• Build and run the Angular Universal project

A module is a container for a group of related components, directives, pipes, and services.

• Modules help organize an application into cohesive blocks of functionality.

• They can be imported and exported to share functionality between modules.

• Angular has a built-in module called the AppModule, which is the root module of an Angular application.

• Modules can be lazy loaded to improve performance.

• Modules can have their own providers to provide services specific to that module.

Angular is a popular front-end framework for building web applications. SPA stands for Single Page Application.

• Angular is a front-end framework developed by Google for building dynamic web applications.

• It uses TypeScript for building applications with components, services, and modules.

• SPA is a web application that loads a single HTML page and dynamically updates the content as the user interacts with the app.

• SPA provides a more seamless user experience by avoiding full page r...read more

Interceptors are used to intercept HTTP requests and responses.

• To add headers, modify requests, or handle errors globally

• Can be used for authentication, logging, caching, etc.

• Example: Adding an authorization token to every request

Some new features in the latest Angular version include Ivy rendering engine, Bazel support, and differential loading.

• Ivy rendering engine for improved performance and smaller bundle sizes

• Bazel support for faster builds and better dependency management

• Differential loading for serving different bundles to modern and legacy browsers

Route guards are used in Angular to prevent unauthorized access to certain routes.

• Route guards can be used to check if a user is authenticated before allowing access to a route.

• There are three types of route guards: CanActivate, CanActivateChild, and CanLoad.

• CanActivate is used to protect individual routes, while CanActivateChild is used to protect child routes.

• CanLoad is used to prevent lazy-loaded modules from being loaded until certain conditions are met.

ActivatedRoute is used to access the current route's information.

• It provides access to route parameters, query parameters, and fragment parameters.

• It can be used to subscribe to route parameter changes.

• It can be injected into a component or service.

• Example: accessing a route parameter in a component using snapshot: this.route.snapshot.params['id']

• Example: subscribing to route parameter changes in a component: this.route.params.subscribe(params => console.log(params))

NGRX is a state management library for Angular applications, inspired by Redux.

• NGRX helps manage the state of an Angular application in a predictable way

• It uses a unidirectional data flow and immutable state

• NGRX consists of actions, reducers, selectors, and effects

• Example: Actions define events that occur in the application, Reducers specify how the state changes in response to actions

Vue is lightweight and easy to learn, while Angular is more powerful and feature-rich.

• Vue is easier to set up and has a smaller learning curve

• Angular has more built-in features and is better for larger projects

• Vue uses a template-based syntax, while Angular uses a component-based syntax

• Vue has better performance in smaller applications

• Angular has better performance in larger applications

Angular 12 is the latest version with updates on Ivy, performance improvements, and new features.

• Angular 12 is the latest version released in May 2021

• Updates include improvements to Ivy compiler, performance enhancements, and new features like strict mode

• Angular Material received updates with new components and features

• Improved support for Webpack 5 and TypeScript 4.2

To reduce bundle size of an Angular application, you can use lazy loading, tree shaking, code splitting, and optimizing assets.

• Use lazy loading to load modules only when needed

• Implement tree shaking to remove unused code

• Utilize code splitting to divide code into smaller chunks

• Optimize assets by compressing images and minifying CSS/JS files

Angular performance improvements involve optimizing code, reducing load times, and minimizing rendering cycles.

• Use lazy loading to only load components when needed

• Optimize change detection by using OnPush strategy

• Minimize DOM manipulation by using ngZone

• Implement server-side rendering for faster initial page load

• Use AOT (Ahead-of-Time) compilation to reduce bundle size

Custom hooks in Angular are functions that allow you to reuse logic across multiple components.

• Custom hooks are created using the @Injectable decorator

• They can be used to share stateful logic between components

• They can also be used to abstract away complex logic from components

• Custom hooks can be tested independently of components

ng-container is a structural directive in Angular used to group elements without creating an extra element in the DOM.

• ng-container is used to group elements together without adding an extra element to the DOM

• It is often used with structural directives like *ngIf and *ngFor to apply logic to multiple elements

• ng-container is not rendered in the final DOM, making it useful for organizing code without affecting the layout

Reactive forms are more flexible and allow for complex form validation and handling, while template driven forms are simpler and rely on directives in the template.

• Reactive forms are defined programmatically in the component class using form controls, form groups, and form arrays.

• Template driven forms are defined in the HTML template using ngModel directive and template variables.

• Reactive forms offer more control over form validation and submission logic.

• Template driven forms...read more

Creating a drop-down in Angular

• Use the element in HTMLUse *ngFor directive to loop through optionsBind the selected value to a variable using [(ngModel)]Use *ngIf directive to conditionally show/hide the drop-down

Angular is a JavaScript framework for building web applications. SPA came in picture for better user experience.

• Angular is a client-side framework developed by Google.

• It allows developers to build dynamic, single-page web applications.

• SPA (Single Page Application) came in picture to provide a better user experience by reducing page reloads and improving performance.

• SPA loads all the necessary resources (HTML, CSS, JS) at once and dynamically updates the content as the user in...read more

ngClass is used to conditionally apply CSS classes to an element in Angular.

• Use ngClass directive in the template with an object or array of classes and conditions

• Classes are applied when the condition is true, and removed when false

• Example:

To load an Angular application, you can use the Angular CLI command 'ng serve' to start a development server.

• Use the Angular CLI command 'ng serve' to start a development server

• Navigate to the project directory in the terminal and run 'ng serve'

• Open a web browser and go to 'http://localhost:4200/' to view the application

Routing guards are used in Angular to control access to certain routes based on certain conditions.

• Routing guards are used to protect routes in Angular applications.

• They can be used to control access based on authentication status, user roles, etc.

• There are different types of routing guards like CanActivate, CanActivateChild, CanDeactivate, CanLoad.

• Example: CanActivate guard can be used to check if a user is authenticated before allowing access to a route.

Ngrx Store is a state management library for Angular applications.

• Centralized state management for Angular applications

• Uses RxJS for reactive programming

• Helps manage application state in a predictable way

• Facilitates communication between components

To call a service in Angular, you need to inject the service into a component or another service and then call its methods.

• Inject the service into the component or service constructor

• Call the service method using the injected instance

Components, modules, and services are different parts of a software system with specific functionalities.

• Components are reusable and independent parts of a system, often encapsulating a specific functionality.

• Modules are larger units of code that group related components together.

• Services are self-contained units of functionality that can be accessed remotely over a network.

• Examples: Component - Button in a UI, Module - User Authentication module, Service - REST API for data ...read more

Translation in Angular can be done using ng-translate or ngx-translate libraries. CSS can be applied using Angular's built-in styles or external stylesheets.

• Use ng-translate or ngx-translate libraries for translation in Angular

• Apply CSS using Angular's built-in styles or external stylesheets

• Utilize Angular's ngClass directive for dynamic CSS classes

Router in Angular is used for navigation between different components and views.

• Angular Router is a powerful tool for building single-page applications

• It allows you to define routes, which are URL patterns that map to specific components

• You can use routerLink directive to navigate between different views

• You can also use router.navigate method to programmatically navigate to a specific route

Observables are used in RxJS to handle asynchronous operations, input/output refers to data flow, ForJoin and MergeMap are operators, interceptors are used for handling HTTP requests.

• Observables are used for handling asynchronous operations in RxJS

• Input/Output refers to the flow of data into and out of a system

• ForJoin is used to combine multiple observables into a single observable

• MergeMap is an operator used to merge observables and map their values

• Interceptors are used in A...read more

Signals in Angular are used to communicate between components or services.

• Signals in Angular are typically implemented using Observables or Subjects.

• They allow components to subscribe to changes and react accordingly.

• Signals can be used to pass data, trigger actions, or handle events.

• Example: Using a Subject to emit a signal when a button is clicked.

Deployment of Angular application involves building the application and hosting it on a server.

• Build the Angular application using 'ng build' command

• Copy the generated files from the 'dist' folder to the server

• Configure the server to serve the Angular application

• Use tools like Jenkins or GitLab CI/CD for automated deployment

Deep dive into .NET Core and Angular

• NET Core is a cross-platform, open-source framework for building modern, cloud-based, internet-connected applications.

• Angular is a popular front-end framework for building dynamic web applications.

• Understanding the architecture, features, and best practices of both .NET Core and Angular is essential for developing robust and scalable applications.

• Integration of .NET Core backend with Angular frontend for creating full-stack applications.

• Uti...read more

Angular uses services, observables, and components for data sharing.

• Angular services can be used to share data between components.

• Observables can be used for asynchronous data sharing.

• Components can communicate with each other using @Input and @Output decorators.

• Shared modules can also be used for sharing data across multiple components.

Lazy loading in Angular is a technique used to load modules only when they are needed.

• Lazy loading is achieved by using the loadChildren property in the route configuration.

• Lazy loaded modules are loaded asynchronously when the user navigates to the corresponding route.

• Lazy loading helps improve the initial loading time of the application by only loading necessary modules on demand.

I integrated Angular code with ASP.NET Core using Angular CLI to generate components and services, and then integrating them into ASP.NET Core project.

• Used Angular CLI to generate components and services

• Integrated Angular code into ASP.NET Core project by adding necessary configurations and dependencies

• Utilized Angular HTTP client to communicate with ASP.NET Core backend APIs

Node.js and Angular work together to create a seamless workflow for backend development.

• Node.js is used for server-side scripting and handling backend logic.

• Angular is used for client-side scripting and creating dynamic web applications.

• Node.js can serve as the backend API for an Angular frontend application.

• Communication between Node.js backend and Angular frontend can be done through RESTful APIs.

Template forms are static while reactive forms are dynamic.

• Template forms are easier to create and maintain.

• Reactive forms allow for more complex validation and dynamic behavior.

• Template forms are suitable for simple forms with few fields.

• Reactive forms are suitable for complex forms with many fields and dependencies.

• Reactive forms use observable streams to manage form data.

• Template forms use two-way data binding to manage form data.

Template driven forms are easier to create and maintain, while reactive forms offer more flexibility and control.

• Template driven forms are created using directives in the template, while reactive forms are created programmatically in the component class.

• Reactive forms offer more control over validation and dynamic form changes.

• Template driven forms are suitable for simple forms with less complex logic, while reactive forms are better for complex forms with dynamic requirement...read more

Structural directives are used to manipulate the structure of the DOM.

• ngIf - conditionally adds or removes an element from the DOM

• ngFor - repeats an element for each item in a list

• ngSwitch - conditionally adds or removes elements based on a value

• ngStyle - dynamically adds styles to an element

• ngClass - dynamically adds classes to an element

ngOnChanges is a lifecycle hook in Angular that is called when input properties of a component change.

• ngOnChanges is used to respond to changes in input properties of a component

• It receives a SimpleChanges object as an argument, which contains the previous and current values of the input properties

• ngOnChanges is commonly used for detecting changes in @Input properties and performing actions based on those changes

Constructor is a method used to create and initialize an object, while ngOnInit is a lifecycle hook used in Angular to initialize components.

• Constructor is a default method of a class that is automatically called when an object is created.

• ngOnInit is a lifecycle hook in Angular that is called after the constructor and is used to initialize data in a component.

• Constructors are used in all classes, while ngOnInit is specific to Angular components.

Angular lifecycles are methods that are called at specific points during the life of a component or directive.

• Angular components have lifecycle hooks that allow you to tap into key moments in the component's lifecycle, such as creation, updates, and destruction.

• Some of the commonly used lifecycle hooks include ngOnInit, ngOnChanges, ngDoCheck, ngOnDestroy, etc.

• These lifecycle hooks can be used to perform tasks like initializing data, detecting changes, cleaning up resources, ...read more

Performance issues in Angular can be handled by optimizing code, reducing HTTP requests, and using lazy loading.

• Optimize code by using trackBy in ngFor loops

• Reduce HTTP requests by using caching and pagination

• Use lazy loading to load only necessary components

• Use AOT compilation to reduce load time

• Avoid using ngIf with heavy computations

• Use ChangeDetectionStrategy.OnPush to reduce change detection cycles

The basic building blocks of Angular are components, templates, directives, services, and dependency injection.

• Components are the building blocks of Angular applications

• Templates define how components are rendered

• Directives add behavior to elements in the DOM

• Services provide functionality that can be shared across components

• Dependency injection is used to provide services to components

The @Input() and @Output() are decorators in Angular used for communication between parent and child components.

• The @Input() decorator is used to pass data from a parent component to a child component.

• The @Output() decorator is used to emit events from a child component to a parent component.

• The @Input() property is bound to a value in the parent component template using property binding.

• The @Output() property is bound to an event in the child component template using event b...read more

Angular is a full-fledged framework while React is a library. Angular uses TypeScript while React uses JavaScript.

• Angular is a complete framework with a lot of built-in features while React is a library that only handles the view layer.

• Angular uses TypeScript, which is a superset of JavaScript, while React uses plain JavaScript.

• Angular has a steeper learning curve but provides more structure and organization while React is easier to learn and more flexible.

• Angular has a large...read more

Difference between == & === and pipes in Angular

• The double equals (==) compares values after type coercion while triple equals (===) compares values without type coercion

• Pipes in Angular are used for transforming data before displaying it in the view

• Pipes can be used for formatting dates, numbers, and strings, as well as filtering and sorting arrays

• Pipes can be chained together to perform multiple transformations on the same data

Routing guard is a feature in Angular that allows to control access to certain routes based on certain conditions.

• Routing guard can be used to prevent unauthorized access to certain routes.

• It can be used to check if the user is authenticated or not before allowing access to a route.

• There are two types of routing guards in Angular: CanActivate and CanActivateChild.

• CanActivate is used to guard a single route while CanActivateChild is used to guard child routes.

• Routing guard can...read more

Angular is a complete rewrite of AngularJS with improved performance and features.

• Angular is a TypeScript-based framework while AngularJS is based on JavaScript.

• Angular has a component-based architecture while AngularJS uses a directive-based architecture.

• Angular has better performance and improved features like server-side rendering and lazy loading.

• AngularJS is no longer supported by Google and has been replaced by Angular.

Pure pipes do not have any side effects and always return the same output for the same input, while impure pipes can have side effects and may not return the same output for the same input.

• Pure pipes are stateless and deterministic.

• Impure pipes can have side effects like modifying global variables or making network requests.

• Examples of pure pipes include filters in Angular, while examples of impure pipes include async pipes in Angular.

A pipe in Angular is used to transform data before displaying it in the template.

• Pipes are used in templates to format data before displaying it to the user

• There are built-in pipes like DatePipe, UpperCasePipe, LowerCasePipe, etc.

• Custom pipes can also be created by implementing the PipeTransform interface

• Pipes can be chained together to perform multiple transformations on the data

Custom directives in AngularJS allow you to create reusable components.

• Create a new directive using the directive() method

• Specify the directive's behavior using the link() method

• Use the directive in HTML using its name as an attribute

• Pass data to the directive using attributes

• Example:

Angular Components are the building blocks of Angular applications.

• Components are reusable and self-contained

• They have a template, styles, and logic

• They can communicate with other components using @Input and @Output decorators

• Examples include navbar, sidebar, login form, etc.

To set up the environment for building an Angular application, you need to install Node.js and Angular CLI.

• Install Node.js and npm

• Install Angular CLI using npm

• Create a new Angular project using CLI

• Run the project using ng serve command

Angular is a JavaScript framework for building web applications. It has a component-based architecture and a well-defined lifecycle.

• Angular lifecycle consists of several phases that a component goes through from creation to destruction.

• The main phases are: ngOnChanges, ngOnInit, ngDoCheck, ngAfterContentInit, ngAfterContentChecked, ngAfterViewInit, ngAfterViewChecked, ngOnDestroy.

• Each phase has a specific purpose and can be used to perform certain actions or manipulate the co...read more

Angular uses various techniques for communication between components.

• Input and Output decorators for parent-child communication

• EventEmitter for custom events

• Services for sharing data between unrelated components

• RxJS for reactive programming and observables

• ViewChild and ContentChild for accessing child components

Guards in Angular are used to protect routes from unauthorized access

• Guards can be used to restrict access to certain routes based on user authentication

• They can be used to redirect users to a login page if they are not authenticated

• Guards can also be used to check user roles and permissions before allowing access to a route