angular 2 interview questions and answers

Top Angular 2 Interview Questions and Answers

That’s right! Angular 2 is a free-source framework for building web-based applications in HTML and Javascript. Google had developed this open-source framework. The initial version, named Angular 1, had not been compatible with mobiles. So, it had been rewritten in NativeScript, to make it compatible with mobiles.

Many companies are seeking employees who are well-versed in Angular 2. Even premium companies like Google use Angular 2. So, Angular 2 open-source front end web framework for software developers is in great demand. Candidates are a bit nervous about the questions which the interview panel will ask them so Vinsys helping with well researched, frequently asked Angular 2 interview questions for experienced and freshers.

So, Angular 2 has a comprehensive list of questions and answers which have been asked during Angular 2 job interviews are given below:

Angular 2 Interview Questions 

1.What is Angular 2 ?

Angular 2 is a free of cost, open-source framework. It is used to build high-performance and low-maintenance web applications.

2.What’s the Difference between Angular JS and Angular 2?

Angular JS is different from Angular 2. The significant differences between Angular JS and Angular 2 are as follows:

  • Angular JS is not compatible with mobiles. Angular two is mobile-friendly.
  • Angular 2 is a thoroughly rewritten version of Angular JS.

3.What are the advantages of Angular 2?

Angular 2 has several advantages. They are as follows:

  1. Browser Compatibility: Angular 2 supports browsers like Internet Explorer 9, 10, 11, Chrome, Firefox and Safari.
  2. Cost-effective: Angular 2 is an open-source platform. So, it is cost-effective.
  3. High performance: Angular 2 utilizes a highly optimized superset of JavaScript. It makes the app as well as the website much faster—moreover, the new component router of Angular 2 results in faster loads.
  4. Cross-platform flexibility: The templates are codes which are highly optimized for the virtual JavaScript machines belonging to the 21st century. It provides the developer with all the benefits of handwritten code. Along with it, it also provides the productivity of a framework.

Furthermore, Angular 2 allows the developers to design applications which may run on desktop systems, Android-based designs and iOS-based designs. So, the apps run across platforms.

  • Mobile-friendly: Angular 2 was created in such a way that it was compatible with mobiles. 
  •  Simpler architecture: Angular 2 has a simpler architecture than other versions because it is component-based.
  • Speed: Angular 2 renders the data faster.
  • Simplicity: Angular 2 makes reading and writing easier.

4.What are some of the features of Angular 2 framework?

The features of Angular 2 framework are as follows:       

  1. Services: Some code sets that are shared between the different codes in an application are known as services.
  2. Typescript: It is a JavaScript Superset, maintained by Microsoft.
  3. Components: Components are used to build applications within various modules.

5 .Name the chief components of Angular 2 ?

The chief components of Angular 2 are as follows:

  • Metadata: Metadata adds more data to the Angular JS class.
  • Modules: The modules break up the application into logical pieces of code. Every module performs a single task.
  • Templates: It defines the views of an Angular JS application.
  • Component: A component brings the modules together.
  • Service: AS service creates a component that may be shared across the entire application.

6.Do you think Angular 2 has certain disadvantages?

 Angular 2 has a few disadvantages. They are as follows:

  1. Steep Learning Curve: It is mandatory for people who are working with Angular 2 to learn TypeScript because it has been introduced to Angular 2. The fundamental functions of Angular 2 are relatively straightforward. As the course advances, the course gets more complicated. So, the learning curve is steep.
  2. Slow, user Interface: The users are prepared to face some steep lag if they need to deal with more than 2000 watchers. 
  3. Inconsistent Documentation: A clear, well-written documentation is missing of a fragmented community. The document is not consistent for the same reason.

7.Who developed Angular 2?

Google invented Angular 2.

8.What do you mean by an Angular 2 directive?

Angular 2 directives are customized elements. They are utilized to extend the power of HTML.

9.What is the full form of CLI? What does CLI do?

CLI stands for Common Line Interface. It is used to create an Angular application. It also helps to make the unit of an application and the end-to-end test of it.

10.How would you handle the Angular application errors?

 All the Angular applications have an option to handle errors. The users need to include the ReactJS catch library. After that, they use the catch function. In turn, the catch function contains a link that guides the users to Error Handler function.

When they are in the Error User function, they send the Error in question to the console. They also send the Error back to the main program so that the operation of the main program is not guaranteed.

After it is set up, all the errors which arise in the future are redirected to the error console of the browser.

11.What role does a decorator play in Angular 2?

 The decorators identify a class or an object type, created by the TypeScript as an Angular component. They also provide extra metadata which dictates how the feature should be processed and used, when it is run.

12.What are the differences between ActivatedRoute and RouterState, in the context of Angular 2?

In the context of Angular 2, there are considerable differences between ActivatedRoute and RouterState. The differences are as follows:

  1. ActivatedRoute is constituted of the data about a route. The route is associated with a component that is loaded in an outlet. On the other hand, the RouterState represents the actual state of a router.
  2. ActivatedRouteSnapchat is necessary to traverse all the activated routes. In the case of RouterState, the router creates a RouterStateSnapshot during navigation. The router creates it after all the redirects have been applied.

13.Differentiate between Component & Directive in Angular 2?

There are many differences between component and Directive in Angular  The differences are as follows:

Only one component is allowed per DOM element Many directives are allowed per DOM element
It is compulsory to use @View Decorator in ComponentThe Directive doesn’t use a view
Components are used to create UI
Directives are used to design
reusable components
Component meta-data annotation is used to register in componentsDirective meta-data annotation is used to register to directives

14.What is Traceur compiler in Angular 2?

A Traceur compiler takes classes, generators and many other features from ECMAScript edition 6. Then, it compiles all the data into JavaScript ES5, which runs on the browser. Hence, the developers may use the code from a future version which has multiple features. The code from future performance also encourages design patterns.

15.What do you mean by event emitter in Angular 2? and how it is work?

An EventEmitter is a class in the Angular framework. It emits custom events. Components and directives use this module to talk about events. In case the users want to propagate a change of the existing element to its children, they use EventEmitter. It reflects the shift in the parent component. 

16.What do you mean by RouterOutlet in Angular 2?

The RouterOutlet may be explained as a directive that is present in the router library, to be utilized as a component. It marks a spot in the template.

 The location allows the router to display the details for that outlet. Each outlet has its name.  

The optional name alternate decides the unique name. The users are not allowed to change the name dynamically after it is set. The default value is kept as primary unless a weight has been established. 

17.What is ViewEncapsulation in Angular?

 ViewEncapsulation defines the variations in template and style encapsulation that are available within the components of a component. Moreover, ViewEncapsulation allows the users to or emulate Shadow DOM according to the requirements.

18.What do you mean by dependency injection in Angular 2?

The healthy framework of Angular gives declared dependency to a class after it is instantiated. The users need to create and register the injectable service to inject it.

19.What do you mean by pipes in Angular data?

 The function of a pipe is to edit and transform the data within the template. It takes input data and transforms it into something we require as the output data. All the versions of Angular, starting from Angular 2 have the feature of pipes. The developers use pipes to write display-value transformation for declaration in their HTML. 

20.How would you explain string interpolation in Angular 2?

Special syntax in Angular two is known as string interpolation. It is an efficient alternative to property binding. Its function is to display dynamic data on an HTML template. It also allows the users to bring about changes in the

21.What do you mean by lazy loading in Angular 2?

 Lazy loading allows the Angular two developers to load different pieces of codes as per demand. It helps an application to load faster. For example, a person may have a retail application with varying departments like grocery, garments and food. In case the user loads all the applications at the same time, the application will work slowly.

Now, lazy learning only helps users view the segments they want. So, it loads only the elements which the user wants to view. Lazy loading uses this technique to make the app load faster.

22.Do you think Angular 2 has many advantages over Angular JS?

 Angular 2 has more advantages over Angular JS. The benefits are as follows:

  • Angular 2 is not only a language. It is a platform.
  • It is modular by nature.
  • The dependency injection of Angular 2 is more straightforward. 
  • Angular two comes with the benefits of Typescript and ES6.
  • Angular 2 has lazy loading features. 
  • It has flexible routing.
  • Angular two is easier to learn than Angular Js.
  • It offers better speed and improved performance.

23.What is the meaning of Spa in Angular 2?

In Angular 2, Spa stands for Single Page Applications. It is a kind of web application which fits into one page. The Spa also lets us navigate seamlessly among pages without refreshing.

The users may parallelly add new data from the backend to call all the codes (HTML and JavaScript) with the help of a single page load at multiple points.

24.How would you optimize the app to get the best performance from it in Angular 2?

 The users need to follow a few steps to optimize the application. The optimization helps them extract the best performance from it in Angular 2. The steps are as follows:

  • They need to use lazy loading while using a large-size app.
  • They need to avoid unnecessary import statements in the application.
  • The application dependency needs to be removed if it is not required.
  • They need to use AOT compilation.
  • Unnecessary third-party libraries need to be removed from the application.

25.What do you mean by Shadow DOM? How does it help the performance in Angular 2?

Shadow Dom is an essential part of Web components standard. It helps the users encapsulate style and DOM tree. When Shadow Dom is added to the web component, the users may apply a scoped style to an element. They don’t showcase the techniques to the external world.

26.What do you understand by Flex layout in Angular 2?

 In Angular 2, Flex layout is a component engine. It allows users to create Flexbox page layouts with a fixed set of directives. These directives are used to design templates. Flex layout has a TypeScript based library. 

 It eliminates the need for style sheets. The layout of Flex has simplified styling. We can say that styling has become more user-friendly, thanks to Flex layout. It also provides intuitive breakpoints while developing, to help design responsive layouts. 

27.How would you define inputs and outputs in Angular 2?

In Angular 2, both input and output are decorators. Information is a decorator that is used to bind a property within a child component. It receives value from the child component. 

On the other hand, the output is used to bind the property of a component to transmit data from the child component to the parent component.

28.What is the meaning of hidden property in Angular 2?

In Angular 2, the hidden property is a particular case binding. It is used to hide stuff.

29.What is Primeng? How would you recommend the use of Primeng with Angular 2?

 Primeng is a rich UI component collection. It is dedicated to The widgets of Primeng are open-source. Hence, they are free to use. Penang is lightweight and powerful. It is optimized for responsive, cross-browser touch. 

30.How would you distinguish between annotation and decorator in Angular 2?

There are a few crucial differences between annotation and decorator in Angular 2. They are as follows:

  • Annotations are hard-coded. Decorators are not hard-coded. 
  • Traceur compilers use annotations. Typescript compilers use decorators.
  • Annotation creates an attribute named “annotations”. It stores arrays and passes metadata to the constructor of an annotated class. A decorator is a function that gets the object which needs to be decorated. A decorator is allowed to change the attributes of the item as required.  

31.How would you explain deep linking in Angular 2?

Deep linking is a process of the URL, which takes the users to specific content directly. It ensures that the users don’t have to cross the application from the homepage while it is taking them to the particular page.

32.What is the factory method in Angular 2?

 Angular 2 offers three ways to create a service: factory, provider and service. The factory function permits the developers to add some logic before the object is created. It returns the created object.

33.What do you mean by Angular UI?

Angular UI is a stack of modules written in angular,js, to make a code more flexible. Its purpose is to simplify the process of development in Angular 2. Those who hae a variety of modules may use the UI for different declarations.

34.Could you name decoder that creates services in Angular 2?

The injectable decoder in Angular 2 allows users to create a service that can be used and injected in Angular JS modules. Angular services allow such services to work.   

Conclusion:  The questions and their answers discussed above help aspiring software developers face the interview panel confidently. Angular 2 is front end web framework for the back end currently AWS is the hottest technology. However, these questions and answers are a few examples. People need to have a clear concept of Angular 2 so that they may face trickier questions easily.