100+ Most Asked Angular Interview Questions and Answers (2024) by agn hub

 

1. Yadneyesh (Curious Coder)

 CodWithCurious.com

 What is Angular? 

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 @Curious_Coder

 Angular is a popular open-source JavaScript framework developed by Google for 

building dynamic web applications.

 2. What are the key features of Angular? 

The key features of Angular include two-way data binding, dependency injection, 

modular architecture, component-based development, and a powerful template 

system.

 3. What is the latest version of Angular? 

As of my knowledge cutoff in September 2021, the latest version of Angular is Angular 

12. However, please note that there may be newer versions available beyond that.

 4. What is the difference between AngularJS and Angular? 

AngularJS, also known as Angular 1.x, is an older version of Angular. Angular, starting 

from version 2, is a complete rewrite of AngularJS with improved performance and 

enhanced features.

 5. What is TypeScript? 

TypeScript is a superset of JavaScript that adds static typing and other advanced 

features to JavaScript. Angular is written in TypeScript.

 6. What is the purpose of the "ng-app" directive in AngularJS? 

The "ng-app" directive is used to define the root element of an AngularJS application. 

It initializes the application and auto-bootstraps the AngularJS framework.

 7. What is a component in Angular? 

A component in Angular is a reusable building block that encapsulates the template, 

logic, and styling required to render a part of the user interface.

 8. What is a template in Angular? 

A template in Angular is an HTML file that defines the structure and layout of a 

component. It includes placeholders and binding expressions to dynamically display 

data.

 9. What is data binding in Angular? 

Data binding is a mechanism in Angular that establishes a connection between the 

component and the template, allowing the synchronization of data between them.

 10. What are the different types of data binding in Angular? 

The different types of data binding in Angular are:

 11. Interpolation ({{}})

 12. Property binding ([ .])

 13. Event binding (( .))

 14. Two-way binding ([( .)])

 15. What is dependency injection in Angular? 

Dependency injection is a design pattern used in Angular to provide dependencies to 

a component from an external source. It helps in creating loosely coupled and 

testable code.

 16. Explain the Angular module and its purpose. 

An Angular module is a mechanism to organize the application into cohesive blocks 

of functionality. It encapsulates components, services, directives, and other features 

required for a specific part of the application.

 17. What is the purpose of NgModule in Angular?

 @NgModule is a decorator that defines a class as an Angular module. It specifies the 

metadata required to configure the module and its dependencies.

 18. What is a service in Angular? 

A service in Angular is a reusable singleton object that encapsulates a specific 

functionality and can be injected into components or other services.

 19. What is the difference between a component and a directive in Angular? 

A component is a type of directive with a template, while a directive doesn't 

necessarily have a template and can be used to extend the behavior of existing 

elements.

 20. What is Angular CLI? 

Angular CLI (Command Line Interface) is a powerful command-line tool that helps in 

initializing, developing, and maintaining Angular applications. It provides various 

commands to generate components, services, modules, etc.

 21. What is the purpose of the "ngFor" directive in Angular? 

The "ngFor" directive is used to iterate over a collection of items in Angular and 

generate the corresponding HTML elements for each item.

 22. What is the purpose of the "ngIf" directive in Angular? 

The "ngIf" directive is used to conditionally display or hide elements based on a given 

expression. It adds or removes elements from the DOM based on the truthiness of the 

expression.

 23. What is Angular Router? 

Angular Router is a built-in module in Angular that provides navigation and routing 

functionality. It allows developers to create single-page applications with multiple 

views and handle navigation between them.

 24. What is lazy loading in Angular? 

Lazy loading is a technique in Angular where modules are loaded on-demand when 

the user navigates to a specific route. It helps in improving the initial loading time of 

the application by loading only the necessary modules.

 25. What is Angular Forms? 

Angular Forms is a set of features and techniques used to handle and validate user 

input in forms. It provides both template-driven forms and reactive forms 

approaches.

 26. What is the difference between template-driven forms and reactive forms? 

Template-driven forms rely on directives in the template to create and handle forms, 

while reactive forms use explicit form controls and reactive programming to manage 

form data and validation.

 27. What is Angular HTTP Client? 

Angular HTTP Client is a module that provides an API to make HTTP requests to a 

server. It simplifies the process of communicating with a backend and handling 

responses.

28. What is Angular Interceptor? 

Angular Interceptor is a feature that allows you to intercept HTTP requests or 

responses before they are sent or received. It is used to modify or handle requests 

globally in an application.

 29. What are Angular pipes? 

Angular pipes are a feature that transforms data before displaying it in the template. 

They are used for tasks such as formatting dates, numbers, and strings, as well as 

creating custom transformations.

 30. What is Angular testing and what are its different levels? 

Angular testing involves writing tests to verify the behavior and functionality of 

Angular components, services, and other parts of the application. It includes unit 

testing, integration testing, and end-to-end testing.

 31. What is TestBed in Angular testing? 

TestBed is an Angular utility that creates a testing module for configuring and 

initializing the environment for unit testing Angular components.

 32. What is Angular CLI command to generate a new component? 

The Angular CLI command to generate a new component is:

 33. Copy code

 34. ng generate component component-name

 35. What is Angular CLI command to generate a new service? 

The Angular CLI command to generate a new service is:

 36. Copy code

 37. ng generate service service-name

 38. What is Angular CLI command to generate a new module? 

The Angular CLI command to generate a new module is:

 39. arduinoCopy code

 40. ng generate module module-name

 41. What is Angular CLI command to start the development server? 

The Angular CLI command to start the development server is:

 42. Copy code

 43. ng serve

 44. What is Angular CLI command to build the application for production? 

The Angular CLI command to build the application for production is:

 45. cssCopy code

 46. ng build --prod

 47. What is Angular CLI command to run unit tests? 

The Angular CLI command to run unit tests is:

 48. bashCopy code

 49. ng test

 50. What is Angular CLI command to run end-to-end tests? 

The Angular CLI command to run end-to-end tests is:

 51. Copy code

 52. ng e2e

 53. What is Angular Material? 

Angular Material is a UI component library for Angular applications. It provides a set of 

pre-built and customizable UI components following the Material Design principles.

 54. What is Angular Universal? 

Angular Universal is a server-side rendering (SSR) solution for Angular applications. It 

allows the application to be rendered on the server and sent as fully rendered HTML to 

the client, improving performance and SEO.

 55. What is Angular Ivy? 

Angular Ivy is the next-generation rendering engine and compiler introduced in 

Angular version 9. It offers improved performance, smaller bundle sizes, and better 

debugging and build times.

 56. What is Angular change detection? 

Angular change detection is a mechanism that detects and propagates changes 

made to data in an application. It automatically updates the view to reflect the 

updated data.

 57. What are Angular lifecycle hooks? 

Angular lifecycle hooks are methods provided by Angular that allow you to tap into 

different stages of a component's lifecycle, such as initialization, change detection, 

and destruction. Examples include ngOnInit, ngOnChanges, and ngOnDestroy.

 58. What is AOT (Ahead-of-Time) compilation in Angular? 

AOT compilation is a process in Angular where the application's templates and 

components are compiled during the build phase rather than at runtime. It results in 

faster rendering and smaller bundle sizes.

 59. What is JIT (Just-in-Time) compilation in Angular? 

JIT compilation is the default compilation mode in Angular, where the templates and 

components are compiled at runtime in the browser. It offers a faster development 

cycle but slightly slower performance compared to AOT.

 60. What is the purpose of the "async" pipe in Angular? 

The "async" pipe in Angular is used to subscribe to an Observable or Promise in the 

template and automatically update the view with the emitted values.

 61. What is ngZone in Angular? 

ngZone is a service in Angular that provides a way to execute code outside or inside 

the Angular zone. It helps in managing change detection and optimizing 

performance.

 62. What is a decorator in Angular? 

A decorator in Angular is a function that modifies a class, property, method, or 

parameter by extending or adding behavior to it. Decorators are used extensively in 

Angular to configure and enhance various parts of the application.

 63. What is tree shaking in Angular? 

Tree shaking is a technique used in Angular (enabled by the underlying TypeScript 

and webpack) to eliminate unused code from the final bundle during the build 

process. It helps in reducing the bundle size and improving performance.

 64. What are Angular schematics? 

Angular schematics are command-line tools provided by the Angular CLI that 

automate the process of generating and modifying code in an Angular application. 

They can be used to generate components, modules, services, and more.

 65. What is ng-container in Angular? 

ng-container is a special element in Angular that provides a way to group multiple 

elements without adding an extra element to the DOM. It is often used in conjunction 

with structural directives.

 66. What is ng-content in Angular? 

ng-content is a placeholder element in Angular that allows the insertion of content 

from the parent component into a child component. It is used to create reusable 

components with customizable content.

 67. What is Angular Renderer? 

Angular Renderer is an API that provides a way to manipulate the DOM directly in 

Angular. It is used when there is a need to modify the DOM that is not covered by 

Angular's declarative templates.

 68. What is ViewEncapsulation in Angular? 

ViewEncapsulation is a feature in Angular that encapsulates the styles of a 

component to prevent them from leaking and affecting other components. It provides 

different encapsulation modes like Emulated, Native, and None.

 69. What is zone.js in Angular? 

zone.js is a library used by Angular to provide a zone-based execution context. It helps 

in tracking asynchronous operations and triggering change detection when needed.

 70. What is the purpose of the "trackBy" function in Angular ngFor? 

The "trackBy" function is used in conjunction with the ngFor directive in Angular to 

improve the performance of rendering lists. It provides away to uniquely identify and 

track items in the collection, allowing Angular to optimize the rendering process by 

reusing existing DOM elements instead of recreating them.

 71. What are Angular decorators like @ViewChild and @ContentChild used for? 

Decorators like @ViewChild and @ContentChild are used to access child elements or 

components in Angular. @ViewChild is used to access a single child component or 

element, while @ContentChild is used to access projected content within a 

component.

 72. What is ng-template in Angular? 

ng-template is a directive in Angular that defines a template block that can be 

conditionally rendered or used as a template for other structural directives like ngIf 

and ngFor. It allows for greater flexibility in rendering dynamic content.

 73. What is the purpose of the "HostListener" decorator in Angular? 

The "HostListener" decorator is used to add event listeners to the host element of a 

component in Angular. It allows the component to listen to and react to events raised 

on the host element.

 74. What is the purpose of the "HostBinding" decorator in Angular? 

The "HostBinding" decorator is used to bind a property of a component to a property 

of its host element. It allows the component to modify or reflect the state of the host 

element.

 75. What is the purpose of the "@Injectable" decorator in Angular? 

The "@Injectable" decorator is used to annotate a service class in Angular. It allows 

the class to be injected with dependencies and enables the Angular dependency 

injection system to create and provide instances of the service.

 76. What is the purpose of the "ngStyle" directive in Angular? 

The "ngStyle" directive is used to dynamically apply styles to an element based on the 

values of expressions in the component. It allows for dynamic styling without directly 

manipulating the CSS classes.

 77. What is the purpose of the "ngClass" directive in Angular? 

The "ngClass" directive is used to conditionally apply CSS classes to an element 

based on the values of expressions in the component. It allows for dynamic class 

binding.

78. What is the purpose of the "ngModel" directive in Angular? 

The "ngModel" directive is used for two-way data binding between a form input 

element and a component property. It allows the component to get and set the value 

of the input element.

 79. What is the purpose of the "ngSwitch" directive in Angular? 

The "ngSwitch" directive is used to conditionally render content based on the value of 

an expression. It allows for multiple cases and provides an alternative to nested ngIf 

statements.

 80. What is the purpose of the "ng-container" directive in Angular? 

The "ng-container" directive is a structural directive that acts as a grouping element 

without rendering any additional element to the DOM. It is often used to apply 

structural directives to multiple elements.

 81. What is the purpose of the "ngZone" service in Angular? 

The "ngZone" service provides a way to execute code within or outside the Angular 

zone. It is used to handle change detection and trigger Angular's rendering cycle.

 82. What is the purpose of the "async" pipe in Angular? 

The "async" pipe in Angular is used to subscribe to an asynchronous data source, 

such as an Observable or Promise, and automatically update the view with the 

emitted values.

 83. What is the purpose of the "ng-content" directive in Angular? 

The "ng-content" directive is used to project content from a parent component into a 

child component. It allows for dynamic composition of components and flexible 

content insertion.

 84. What is Angular Material CDK? 

Angular Material CDK (Component Dev Kit) isa set of tools and utilities provided by 

Angular Material that helps in building custom, reusable UI components. It provides 

features like drag and drop, virtual scrolling, overlays, and more.

 85. What is Angular Ivy Renderer? 

Angular Ivy Renderer is the rendering engine introduced with Angular Ivy. It is 

responsible for transforming the component template into executable code, 

optimizing rendering performance, and enabling features like incremental DOM 

updates.

 86. What is the purpose of the "ngOnInit" method in Angular? 

The "ngOnInit" method is a lifecycle hook in Angular that is called once, after the 

component has been initialized and its inputs have been bound. It is commonly used 

to perform initialization tasks.

 87. What is the purpose of the "ngOnChanges" method in Angular? 

The "ngOnChanges" method is a lifecycle hook in Angular that is called when one or 

more input properties of a component change. It allows the component to respond to 

changes in input values.

 88. What is the purpose of the "ngDoCheck" method in Angular? 

The "ngDoCheck" method is a lifecycle hook in Angular that is called during every 

change detection cycle. It is used to implement custom change detection logic and 

perform manual checks for changes.

 89. What is the purpose of the "ngAfterViewInit" method in Angular? 

The "ngAfterViewInit" method is a lifecycle hook in Angular that is called after the 

component's view has been fully initialized. It is used to perform tasks that require 

access to the rendered DOM elements.

90. What is the purpose of the "ngAfterViewChecked" method in Angular? 

The "ngAfterViewChecked" method is a lifecycle hook in Angular that is called after 

every check of the component's view. It is used to perform tasks that need to be 

executed after the view has been checked for changes.

 91. What is the purpose of the "ngOnDestroy" method in Angular? 

The "ngOnDestroy" method is a lifecycle hook in Angular that is called just before a 

component is destroyed and removed from the DOM. It is used to perform cleanup 

tasks and unsubscribe from subscriptions.

 92. What is the purpose of the "ngContent" selector in Angular? 

The "ngContent" selector is used in the template of a component to define a content 

projection slot. It allows the component to accept and render content provided by its 

parent component.

 93. What is Angular Ivy's differential loading? 

Angular Ivy's differential loading is a feature that generates different bundles for 

modern browsers and older browsers. Modern browsers receive a smaller bundle with 

ES2015+ syntax, while older browsers receive a larger bundle transpiled to ES5 syntax.

 94. What is the purpose of the "ngZone.runOutsideAngular()" method in Angular? 

The "ngZone.runOutsideAngular()" method is used to run a specific code block outside 

the Angular zone. It helps to prevent unnecessary change detection cycles and 

improves the performance of the code executed within the block.

 95. What is the purpose of the "NoopAnimationsModule" module in Angular? 

The "NoopAnimationsModule" module is a module provided by Angular that disables 

animations in Angular Material components. It is useful in scenarios where animations 

are not desired or need to be turned off for testing purposes.

 96. What is the purpose of the "@Host" decorator in Angular? 

The "@Host" decorator is used in Angular to restrict the dependency resolution to only 

the host component, excluding any parent components. It ensures that the 

dependency is obtained from the immediate host component.

 97. What is the purpose of the "preserveWhitespaces" configuration in Angular 

templates? 

The "preserveWhitespaces" configuration in Angular templates is used to control 

thehandling of whitespace characters in the template. When set to "true", it preserves 

all whitespace characters, including line breaks and spaces. When set to "false" or not 

specified, it removes unnecessary whitespace characters to minimize the size of the 

rendered HTML.

 98. What is Angular Material Theming? 

Angular Material Theming is a feature that allows customization of the visual 

appearance and style of Angular Material components. It provides a way to define 

custom color palettes, typography, and other style attributes to create a unique look 

and feel for the application.

 99. What is the purpose of the "RouterOutlet" directive in Angular? 

The "RouterOutlet" directive is used in Angular to define the location where the router 

should render the components associated with different routes. It acts as a 

placeholder for dynamically loaded components.

 100. What is the purpose of the "resolve" property in Angular route configuration? 

The "resolve" property in Angular route configuration is used to specify a set of data to 

be resolved before activating a route. It allows for fetching data from a server or 

performing other tasks asynchronously before the route is activated.