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Angular is a robust front-end JavaScript framework widely used for application development. With its growing popularity, Angular developers are in high demand.
This blog will show some of the top Angular Interview questions that represent frequently asked questions and how to answer them. The questions are at an advanced level of Angular.
 
So below is the list of the top and their relevant answers.

Top 20 Angular interview questions


 

1. Why was Angular presented as a client-side framework?


Developers have traditionally used VanillaJS and jQuery to develop busy websites. As websites became more complicated, with added features and functions, it became increasingly difficult for developers to maintain the code. Additionally, jQuery did not provide any facilities for handling data across views.
Angular was created to solve these problems, making it easier for developers by breaking the code into smaller pieces of information known as Components in Angular. Client-side frameworks allow the development of advanced web applications such as SPAs, which, if developed by VanillaJS, is a slower process.
 

2. What is ViewEncapsulation, and how many ways can it be done in Angular?


Simply put, ViewEncapsulation determines whether styles defined in a particular component affect the entire application or not. Angular supports 3 types of ViewEncapsulation:
Emulated: Styles used in other HTML are extended to the member.
Native: Styles used in other HTML are not propagated to the member.
None: Styles defined in an element are visible to all members of the application
 

3. List some benefits of Angular over further frameworks.


Some of the benefits of Angular over further frameworks are:
Box Features: There are several built-in features such as routing, state management, rxjs library, and HTTP services.
Declarative UI: Angular uses HTML to render an application's UI because it is a declarative language that is much easier to use than JavaScript.
Long-term Google asset: Google plans to attach with Angular and continue to expand its ecosystem as it offers long-term support for the framework.
 

4. Explain the digest cycle in Angular


Following a watchlist to watch for changes in the value of a watch variable is called a digest cycle in Angular. The previous and current versions of the range model values ??are compared in each digest cycle.
Although the digest process is started by default, it is possible to start it manually using the $apply() function.
 

5. Can we render an Angular app server-side?


Yes, we can, with Angular Universal. The benefits of using Angular Universal are:
Better User Experience: This allows users to instantly see the app view.
Better SEO: Universal ensures that content is available on every search engine, leading to better SEO.
Faster loading: Rendering pages open earlier to browsers, so the server-side application loads faster.
 

6. Explain Dependency Injection.


Dependency injection is an application design pattern implemented by Angular and forms the core ideas of Angular.
Dependencies in Angular are assistance that simply has some functionality. Components and directives in your application may require these features. Angular delivers a smooth mechanism by which these dependencies are injected into parts and messages.
 

7. What are services in Angular?


Singleton objects in Angular created only once during the application's lifetime are called services. An Angular service contains methods that persist data throughout the application's lifetime.
The primary intent of Angular is to organize and share business logic, models or data, and functionality with the various components of an Angular application.
Functions offered by Angular can be called from any Angular component, such as a controller or directive.
 

8. What are some features of Angular 7?


Unlike previous versions of Angular, the 7th major release comes with the @angular/core split. This is done to reduce the size. Not every module requires an Angular developer. Therefore, in Angular 7, each @angular/core split will have no more than 418 modules.
Angular 7 offers drag and drop and virtual scrolling. Finally, it also has a new and improved version of the ng compiler.
 

9. What is string interpolation in Angular?


String interpolation in Angular, also known as whisker syntax, refers to a specific type of syntax that uses template expressions to display component data. These template expressions are enclosed in double braces, i.e. {{ }}.
The JavaScript expressions executed by Angular are enclosed in curly braces, and the corresponding output is inserted into the HTML code. Typically, these terms are updated and registered like clockwork as part of the digest cycle.
 

10. Explain Angular Authentication and Authorization.


User credentials are passed to an authenticated API that is on the server. A JWT (JSON Web Token) is returned after validating server-side certifications. A JWT has information or attributes about the current user. The user is then recognized with the given JWT. This is called authentication.
After successful login, different users have different access levels. While some have access to everything, for others, access may be limited to only some resources. The access level is an authorization.
 

11. What is a SPA (single-page application)? Compare SPA technology with traditional web technology.


Only one page - index.HTML - is maintained by SPA, although the URL constantly changes. SPA technology is snappier and more comfortable to develop than traditional web technology.
In conventional web technology, a server sends a resource as soon as a client requests a web page. However, when the client requests another page again, the server reacts by sending the requested resource. The issue with this technology is that it needs a lot of time.
 

12. What is Data Binding? How many ways can this be done?


Data binding connects application data to the Data Object Model (DOM). This happens between the template (HTML) and the component (TypeScript). There are 3 ways to accomplish data binding:
Event Binding: This allows the application to respond to user input in the target environment.
Property Binding: Allows interpolation of values ??calculated from application data into HTML.
Two-way binding: Changes made to the application state are automatically reflected in the view and vice versa. A model directive is used to achieve this type of data binding.
 

13. What are templates in Angular?


Angular templates, written in HTML, contain Angular-specific attributes and elements. Combined with information from the driver and model, the templates are further rendered to suit the dynamic view user.
 

14. Explain the difference between annotation and decorator in Angular.


In Angular, annotations are used to construct an annotation array. They are the only class metadata set using the Reflect Metadata library.
Decorators in Angular are design patterns used to separate the decoration or modification of a class without changing the original source code.
 

15. What are directives in Angular?


Directives are the component of Angular. They allow developers to write new application-specific HTML syntax. In fact, directives are functions executed by the Angular compiler when it finds them in the DOM. Directives are of three types:
?      Attribute directives
?      Components Directive
?      Structural guidelines
 

16. What are the differences between Angular and jQuery?


The single most significant difference between Angular and jQuery is that while the former is a front-end JS framework, the latter is a JS library. Despite this, some similarities exist, such as DOM manipulation and animation support.
However, the notable dissimilarities between Angular and jQuery are:
Angular has two-way data binding, whereas jQuery does not
Angular delivers assets for RESTful APIs, while jQuery does not
jQuery does not offer deep-link routing, although Angular supports it
There is no form validation in jQuery while it is present in Angular
 

17. Could you explain the dissimilarity between Angular expressions and JavaScript expressions?


However, both Angular expressions and JavaScript expressions can include literals, operators, and variables, there are some differences. The fundamental differences between Angular expressions and JavaScript expressions are listed below:
 
Angular expressions endorse filters, while JavaScript expressions do not.
It is feasible to write Angular expressions in HTML tags. JavaScript expressions, on the other hand, cannot be written inside HTML tags.
While JavaScript expressions support conditions, exceptions, and loops, Angular faces do not.
 

18. What is a square material?


It is a library of user interface components. Angular Material helps create attractive, consistent, and fully functional websites and applications. It follows modern web design principles, including browser portability and graceful degradation.
 

19. Why TypeScript over JavaScript in Angular?


TypeScript is a superset of Javascript because it's Javascript plus features like variable typing, annotations, and variable scoping, among others. It is pure object-oriented programming and offers a compiler that can convert it to Javascript-equivalent code.
 

20. How are Observables different from Promises?


Once the promise is made, the implementation takes place. However, this is not the issue with observables because they are lazy. This means nothing happens until the subscription is made.
While promises handle a single event, an observable is a stream that allows more than one event to pass through. A callback is produced for each event in the visual.
 

Conclusion


In this blog, we have seen the top 20 Angular interview questions and their suitable answers. We hope this blog helps you learn on your learning journey.