Angular 4 Interview Questions and Answers

Unit testing or private testing is used to test the system’s components. This process is s best practice to test small separate pieces of code. If the unit testing depends on any of the external resources such as networks, APIs and databases, then it won’t be listed as a unit test.

ElementRef is basically a class or reference types used for abstraction. The class structure holds the native elements and ElementRef is used to access the native elements

@Component({
selector: 'sample',
...export class SampleComponent{
constructor(private hostElement: ElementRef) {
   //outputs
   console.log(this.hostElement.nativeElement.outerHTML);
}

ElementRef is used to break the abreaction rather than using specific API DOM like textContent

Angular 4 services contain functions or methods that consistently maintain the data of an application throughout its life which implies that data will remain secure and available at all times. The main aim of angular 4 services is to share business logic, data, information, models with several components of angular 4 applications.

Note: Our aim while creating Angular 4 Interview Questions, is to help you grow as a Angular Developer. The questions mentioned here have been asked by leading organizations during technical rounds of the interview process.

In general, deep linking takes a specific page directly without searching and traversing application from the landing page. It helps in generating and getting indexes so that the specific links can be easily searched by the search engines.
Angular 4 support deep linking using ‘#’

We can use the ngx-cookie-service node package to save cookies in Angular 4.

Use the following steps:

• Install the node package with the following syntax:
  npm install ngx-cookie-service –save
• Now, we have to add the cookies service to app.module.ts as a provider.
  @NgModule({
    ...,
    providers: [ CookieService ]
})
• Further, continue by importing and injecting it into a component.
  import { CookieService } from 'ngx-cookie-service';
constructor( private cookieService: CookieService ) { }
ngOnInit(): void {
this.cookieService.set( 'Test', 'Hello World' );
this.cookieValue = this.cookieService.get('Test');
}

There are three types of loading namely eager loading, lazy loading, and preloading. In general, eager loading is a module that needs to import into the Angular 4 application module by importing metadata of @NgModule decorator. Additionally, eagerly loading is useful for small size angular applications in which all feature modules will be loaded before starting of the application.

JavaScript

JavaScript is a programming language designed for web pages. It is developed by Netscape and Sun and it is initiated by Netscape and called LiveScript. It is used to enhance web pages with dynamic and interactive features.

ECMAScript

ECMA is an abbreviated form of European Computer Manufacturer's association. In general, ECMAScript is a standard used in scripting languages such as Jscript, JavaScript.