Angular 4 Interview Questions and Answers

Last updated on Feb 07, 2024
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Angular 4 Interview Questions

Angular 4, released in March 2017, is a JavaScript framework for building apps in HTML, JavaScript, and TypeScript. Angular 4 offers built-in features for HTTP service, animation, and materials. This is an essential topic in the Angular 4 Interview Questions for experienced professionals. The unique feature in Angular 4 is that starting from Angular 4, developers will be able to query ParamMap in the router.

Quick Facts About Angular 4
What is current angular version? Angular 11.0. released on 11th November 2020
Angular4 is Developed by Google
What language does Angular use? TypeScript
When was Angular first released? 20th October 2010
When was Angular4 released? 23rd March 2017
Which is the best free IDE for Angularjs? Sublime Text, Visual Code, Atoms, etc
What is the best Angular version of web development? For the development, Angular 2 and 4 both are good.

Most Frequently Asked Angular 4 Interview Questions

Here in this article, we will be listing frequently asked Angular 4 Interview Questions and Answers with the belief that they will be helpful for you to gain higher marks. Also, to let you know that this article has been written under the guidance of industry professionals and covered all the current competencies.

Q41. What is the difference between Angularjs 4 and AngularJS?

Angular 4 is the upgraded version of AngularJS, which is the very first introduction of AngularJS. The newer version Angular 4 has fulfilled several drawbacks of its predecessor and introduced excellent features such as Router ParamMap support, Dynamic Components with NgComponentOutlet, latest TypeScript functions, simplified HTTP request, better Animation package, mobile-oriented framework, server-side run and more, which were are not available with the AngularJS.

Q42. What is shadow dom?

While creating an Angular 4 component, a shadow DOM is created by default and our template gets loaded into it. It’s a DOM element subtree which renders as part of the document but not into the present main document DOM tree. It is used by browsers to determine the rendered object on the page. JavaScript programs use it to modify content, page styling and structuring.

Q43. How to debug angular 4 projects from visual studio 2017?
To debug Angular 4 projects using visual studio 2017, we have to follow the below-mentioned steps.
  • Create our project as Asp.Net Core Web Application and use the “Angular” project template.
  • Next to "IIS Express", click the down-arrow to set the web browser to Google Chrome.
  • Run debugging and the script debugging being enabled message will pop up by Chrome.
  • Continue further by setting a breakpoint on "this.currentCount++;"in counter.component.ts.
  • Now visit the Counter screen to click Increment and the breakpoint set will be hit.
  • While performing this, make sure to turn off the Chrome Developer Tool running

Note- make sure that your chrome developer tools will run on the same time during the process of debugging

Q44. Why we need Ngmodel in angular 4?

We need Ngmodel in angular 4, as it possesses the property of binding and encapsulating the input elements of DOM. In short, we need Ngmodel in angular 4 for two –way-data-binding process.

Q45. What is Angular 4 and why it is used?

Angular 4 is an advanced JavaScript framework which uses HTML, JavaScript, and TypeScript web applications and APK apps. It’s a superset of JavaScript and offers excellent built-in features for HTTP service, animation, navigation, menus, toolbar, materials, etc.

Q46. What are the difference between angular 2 and 4?
Here are a few significant differences between Angular 2 and 4 which developers are going to notice.
  • Angular 4 has many inbuilt animation packages which were missing in Angular 2.
  • Angular 4 has its template tag called “ng-template.” The previous version uses only “template.”
  • Compared to Angular 2, in the newest version, developers can use else syntax with Nglf for excellent UI handling.
  • A new template syntax addition “as keyword” in Angular 4 which can be used to simplify to the “let” syntax.
  • Simplified “HTTP request” and application testing in Angular 4.
Q47. Explain the difference between angular and AngularJS?

AngularJS is the very first version of the Angular. A tool named AngularCLI is used to generate Angular components. Angular JS which is a client-side framework works with JavaScript and still supported but not compatible with Angular any more. Simplifying it, AngularJS is the old version and Angular is the newest one.

Q48. How we can set Http Request Header in Angular 2 and Angular 4?

To set Http Request Header in Angular 2, create the HTTP Client Injectable class and inject the HttpClient object in the Component. Developers use HTTP Interceptors to set Http Request Header in Angular 4. To achieve this. Write an interceptor for adds a header for every request and after creating the interceptor, register it using HTTP_INTERCEPTORS in the @NgModule().

Q49. How to create a new component using CLI in Angular 4?
To create a new component in Angular 4 using CLI,
  • Open Project Directory
  • Run any one of the below mentioned the syntax

We have the most extensive question bank to help you answer Angular 4 interview questions and answers.


ng component name


ng generate component componentname

Q50. How to upgrade angular 2 project to angular 4? Explain

No coding level changes are required to enhance a project present in Angular 2 to Angular 4. Users only have to update the tsconfig.json and package.json files. Some minor adjustments may be needed depending on project types. After updating the data, clean out your node_modules directory, run npm install and npm start and you will be started with the Angular 4.

This means a request for the route- and the query parameter can be assigned to a route. Until Angular 2, route parameters were stored in a key-value object and were accessible through standard JavaScript syntax. Do you want to succeed in your Angular 4 Interview Questions and Answers? Read on!

Another unique feature is that the functions that were necessary for animations are placed in their package. This has been done to avoid creating unnecessary bundles of significant size. Until Angular 2, these functions were offered as part of the core module and were always included even if they were not getting used in apps.

In angular 4, the use of decorators is done extensively for compiling the code. There are four types of decorators – Class, Property, Method, and Parameter.

Type security and speed ngc-Compilerhave improved in Angular 4 as compared to Angular 2. If you are scrolling on the web for angular 4 interview questions and answers pdf, then this guide will gonna help you.

Reviewed and verified by Umesh Singh
Umesh Singh

My name is Umesh Singh having 11+ experience in Node.JS, React JS, Angular JS, Next JS, PHP, Laravel, WordPress, MySQL, Oracle, JavaScript, HTML and CSS etc. I have worked on around 30+ projects. I lo...