Top Angular 2 Interview Questions and Answers - Essential Guide for Job Seekers

Last updated on Feb 07, 2024
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Angular 2 Interview Questions

To survive in the modern industry and to earn a very good salary, learning only JavaScript programming language is not sufficient, you must move on to learning JavaScript Frameworks also i.e., Angular. It doesn’t matter if you are thinking to start your career in software development or are already a software developer, you will always find Angular 2 Interview Questions useful. This is an open-source component-based UI framework that is written in TypeScript and is mainly used in building web, mobile, and desktop applications in HTML and JavaScript. Angular is an evolved and upgraded version of Angular JS and is invented by Google. For writing codes, Angular provides many language choices like Typescript, Dart, ES5, ES6. It supports both data and property blinding which allows a user to control DOM i.e., Data Object Model by binding class and HTML properties.

Quick Facts About Angular 2
What is the latest version of Angular? Angular 14 released on 2nd June 2022
When did angular 6 release? 14th September 2016
Who is the developer of Angular 2? Google
What language does Angular use? TypeScript
License MIT License
Official website

Frequently Asked Angular 2 Interview Questions for Developers

Here in this article, we will be listing frequently asked Angular 2 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.

Q31. How would you optimize the application for better performance in angular 2?

To optimize an application for optimal performance in Angular 2, we have to follow the below-mentioned steps.

  • Use of AOT compilation.
  • With a large-size app, use lazy loading instead of the fully bundled app.
  • Avoid un-necessary import statements in the application.
  • Remove unused and unnecessary 3rd party libraries from the application.
  • If not required, consider removing application dependencies.
Q32. Is angular 2 Object Oriented?

Yes, Angular 2 is a true object-oriented development framework.

Q33. What is the purpose of tsconfig.json in Angularjs?

It allows us to specify the root level files. The compiler options required to compile a TypeScript project. It determines that the said directory is the TypeScript project root. Here is a JSON file describing to define a tsconfig.json file containing different parameters of the compilerOptions property:


    "compilerOptions": {
    "noImplicitAny": true,
    "module": "system",
    "removeComments": true,
    "strictNullChecks": true,
    "sourceMap": true,
    "allowUnreachableCode": false,
    "outFile": "../JS/TypeScript/BestInterviewQuestion.js"

Here is an example of these options.
  • target: It is used for the compiled output.
  • module: It is used in the compiled output. the system is for SystemJS, common for CommonJS.
  • moduleResolution: It is used to resolve module declaration files (.d.ts files). With the node approach, they are loaded from the node_modules.
  • sourceMap: generate or not source map files to debug your application.
  • emitDecoratorMetadata: emitDecoratorMetadata emit or not design-type metadata for decorated declarations in the source.
  • experimentalDecorators: It enables or not experimental support for ES7 decorators,
  • removeComments: remove comments or not
  • noImplicitAny: It is used to allow or not the use of variables.
Q34. What is tree shaking?

The Tree Shaking is a concept of dead code elimination from projects. The code present in your project but neither referenced nor used will be dropped here. It will eliminate the unused modules during the build process, making user application lightweight.

Q35. How to define custom typings to avoid editor warnings?

To avoid editor warning whilst defining customized typings, we have to prolong the kind definition for an external library as a accurate practice. Without altering any node_modules or current typings folder, we have to create a new folder named “custom_typings" and put all our customized kind definitions there.

Q36. What is shadow dom and how it is helping to perform better in angular 2?

Shadow DOM is an integral part of Web Components standard while enables users for style encapsulation and DOM tree. It helps users to hide DOM logic behind other elements. With the addition to it, we can also apply scoped styles to elements without showcasing them to the outer world.

Q37. How you can load external css style?

To allow a load of external CSS styles in Angular 2 to affect component contents, we have to change view encapsulation which presents styles to components referring “bleed into”.

   selector: 'some-component',
   template: '<div></div>',
   styleUrls: [
   encapsulation: ViewEncapsulation.None,
export class SomeComponent {}

Q38. How to create a singleton service in Angular 2?
Here is the steps to create a singleton service-
  • Import the injectable member using import {Injectable} from '@angular/core';
  • Import the HttpModule, Http and Response members’ as import { HttpModule, Http, Response } from '@angular/http';
  • Add the decorator @Injectable()
  • Export –
    export class UserService {
       constructor(private _http: Http) { }
Q39. What is the difference between annotation and decorator in Angular 2?
Annotation Decorator
Used by Traceur compiler Used by Typescript compiler
Annotation creates the attribute ‘annotations’ that stores arrays and pass metadata to the constructor of the annotated class. It is a function that gets the object that needs to be decorated (or constructed). They can change the attributes of the object as necessary.
Annotations are hard-coded Not hard-coded
Example – import {Component} from 'angular2/angular2'; Example - import {ComponentAnnotation as Component} from 'angular2/angular2';
Q40. What is the use of polyfills.ts file in Angular 2?

In Angular 2, the polyfills.ts file is used to make user application compatible for various browsers. The code we write in Angular 2 is mostly in ES6, which is not compatible with Firefox or IE, and requires few environmental setups before they wither get viewed or used in browsers.

Angular offers Polyfills.ts file to help users with the required setup.

Tips to Crack Angular 2 Interview Questions
  • Angular Interviews are not just about learning Java Concepts but one of the toughest questions is to know about software and system designs.
  • Practice is the key factor to crack any type of interview. Angular interviews are no exception too.
  • You should know about basics such as TypeScript, Services, Metadata, Components, etc.
  • If you know about the answer but you are taking too much time to explain it, then that land you nowhere. So yes, Time Yourself i.e. answer your question within a time limit.
  • Teach a concept to your friend or anyone which you have learned. By this, you will know if you learn that concept.
  • Honesty is the best policy. If you don’t know the answer just admit it without wasting the interviewer and your time.
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...