Angular 2 is the higher version of Angularjs.The complete rewrite of Angularjs framework is known as Angular 2.It is a open source javascript framework to build web applications.AngularJS is based on MVC(Model View Controller) whereas Angular2 is component based architecture.AngularJs does not support mobile development whereas Angular 2 fully supports mobile development.

This article covers topic such as 'Why should i go for angular','prerequisties of angular2','purpose of prerequisites','how to install prerequisites','Angular4 features','Modules','components','templates','Different types of modules in angular', 'routing','navigation','angular CLI commands','About template forms','About Reactive forms','using services','Observable','Observer','Rxjs' and angular common problems and their solutions.

After Angular 2, so many versions are released like Angular 4,Angular 6,Angular 8 and now Angular 9.Each version is not complete rewrite but has got some extra features than the previous versions.Now Angular 8 supports web workers.Web workers allows you to run CPU intensive manipulation to run in background thread,freeing the main thread and there by UI will be more responsive. Angular 8 introduces Bazel build tool.It does incremental build means it will only build what has changed since the last build.The first build take some time,but subsequent builds should take less time.
To implement this in an existing application, run
ng add @angular/bazel