What is application bootstrapping in angular ?

 Bootstrapping is the process of starting application in angular. 

The entry point for an angular application is index.html. 

Index.html loads required javascripts. Then angular loads the main module and components which are by default app.module and app.component. 

Angular booting is a six step process: 

Load index.html
Load Angular, Other Libraries, and App Code
Execute main.ts File
Load App-Level Module
Load App-Level Component
Process Template

https://www.pluralsight.com/guides/bootstrapping-an-application-in-angular

https://angular.io/guide/bootstrapping

Angular NgModule is a component which specifies how different part of the application fit togather.

@NgModule decorator takes  four metadata objects: 

declarations

imports

providers 

bootstrap

Frequently used Angular modules 

BrowserModule

CommonModule  (NgIf and NgFor)

FormsModule

ReactiveFormsModule

RouterModule

HttpClientModule

Note that BrowserModule imports CommonModule and re-exports it.