Angular 8 Interview Questions

Angular 8 Interview Questions
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Below are the list of Best Angular 8 Interview Questions and Answers

Angular 8 is the latest version of the most popular JavaScript framework that is used to develop front-end mobile apps, desktop apps, and SPAs (Single Page Applications). It is an open-source, typescript-based JavaScript framework that is used to create dynamic client-side web applications. It is written in TypeScript but compiled to JavaScript.

AngularJS is developed and maintained by Google. The latest version of this framework is released on May 28, 2019.

It contains features like differential loading, web workers, dynamic imports, and Angular Ivy. This latest version also supports TypeScript 3.4.

Some of the new features in Angular 8 are,

  • It supports TypeScript 3.4. All the angular 8 applications now need TypeScript 3.4 to run.
  • It now supports the Web worker class. It frees the main thread to update the user interface while it facilitates the CPU intensive computations in the background thread.
  • It has a new compiler called Ivy rendering engine and a new build system called Bazel. It has features that enable you to build a CLI application more quickly.
  • With Angular 8, you can facilitate dynamic import syntax instead of lazy-loaded modules.
  • Angular 8 now also has an improved ngUpgrade.

Angular CDK (Component Development Kit) is comprised of tools, services, components, classes, and modules that are used by the developers to build components of the web. It represents an abstraction of the functionalities in the Angular material themes. So, it can be used to leverage the features of the Angular Material without adopting the material design language.

CDK is an open-source toolkit that is released under the @angular/CDK npm package.

The wildcard is the last route in the appRoutes array of routes specified by the **path. This route will be selected by the router if the requested URL doesn’t match any of the paths defined in the earlier configuration. It is mainly used in displaying a “404 - Not Found” page or to redirect to another route.

A service worker is nothing but a script that is used to manage the caching for an application while running in the web browser. It augments the traditional web deployment model to deliver a user experience that provides performance and reliability that is equal to the natively installed code. Adding a service worker is one of the steps in turning your application into a PWA (Progressive Web Application). It also functions as a network proxy that intercepts all the outgoing HTTP requests and responds. It loads first when the application is loaded and intercepts every request to load the application.

HostListener in Angular is a function decorator. It accepts an event name as the argument and calls the associated function when the event gets fired on the host element.

@HostListener('mouseover') onHover() { 

Here, when you hover the mouse on the host element, an alert popup will be triggered.

HostBinding is used to bind the input properties in the host element to the directive. With the HostBinding decorator, a directive can link internal property to the input property of the host element. When the internal property is changed, the input property of the host element will change too.

The typeof is a JavaScript keyword that is used to check if the type of the value. It checks if the value is of the primitive type.

If (typeof value == ‘string') 

The ngx-build-modern in Angular is used to extend the CLI build process without ejecting it. It creates an optimized bundle for the modern browser as well as legacy bundles for old browsers. It even makes the browser load the right set of bundles. It automated all this process by providing a CLI extension.

Ivy is the new compilation and rendering pipeline engine that is used from the Angular version 8. You can create a new project with Ivy enabled engine or use the Ivy engine in your existing project.

Bazel is the new tool available in the Angular version 8 that allows you to break an application into distinct build units at the NgModule level. With this, you can rebuild the part of the code that is changed instead of rebuilding the entire application.

In Angular, directives are just a function that is executed whenever the compiler finds the directive function in the DOM. With these functions, you can change the appearance or behavior of a DOM element.

There are three kinds of directives present in the Angular.

  • Component Directive – It has a template.
  • Structural Directive – It is used to add or remove DOM elements thus changing the layout.
  • Attribute Directive – It is used to change the appearance or behavior of an element.

Microsoft FED (Front End Development) Angular uses Microsoft’s TypeScript language. It is a superset of ECMAScript (ES6) and has the advantages of TypeScript features like type declarations, and the advantages of ES6 too like iterators and lambda.

Some of the popular technologies used to create Angular 8 applications are,

  • Karma – It is a testing framework for Angular development that provides an environment to test your application on real browsers, phones, and tablets.
  • Protractor – It is also an end to end test framework that is built on top of WebDriver JS.
  • - It is used to introduce mentions and macros widgets with no dependencies on jQuery.
  • Angular Kickstart – It speeds up the development process of your AngularJS application.
  • AngulatFire – It is a flexible API that is used to create backend in your Angular application.

The AngularJS Animate library is used to include animations in your application. Here, the ngAnimate module should be added to your application.

Some of the pre-defined classes in the ngAnimate are ng-show, ng-hide, ng-class, ng-view, ng-include, ng-repeat, ng-if, and ng-switch.

The Angular Universal is a technology that is used to render angular applications on the server. Instead of executing Angular application in the browser, angular universal executes the application on the browser. It renders application quickly than the regular rendering on the browser. Therefore, the user can quickly view the application layout.

The Tree Shakeable Providers are used to define services and to be used by the dependency injection system in the Angular. It is used in a way that improves the performance of the angular application.

The Tree Shakeable Provider mechanism provides the benefits of tree shaking performance and dependency injection. The tree shaking mechanism refers to the process of removing unused code and including only the code that is needed for the application to run.