Why Angular export empty class in app.modules.ts?

Question

I am new in Angular, I am using Angular 4, and I made an app using the Angular CLI, by ng new command.

In main.ts, we have

 ...
import {AppModule} from './app/app.module';
 .
 .
platformBrowserDynamic().bootstrapModule(AppModule);

and AppModule is defined (as you see) in app/app.module, here is what we have in app.module.ts:

import { BrowserModule } from '@angular/platform-browser';
import { NgModule } from '@angular/core';
import { FormsModule, ReactiveFormsModule } from '@angular/forms';

import { AppComponent } from './app.component';

@NgModule({
  declarations: [
    AppComponent
  ],
  imports: [
    BrowserModule,
    FormsModule
  ],
  providers: [],
  bootstrap: [AppComponent]
})
export class AppModule { }

As you see it says export class AppModule { }, and it also used in platformBrowserDynamic().bootstrapModule(AppModule);

Can someone please explain this for me?

Answer 1

The body of the class is indeed empty. But that decorator above the class (@NgModule) is giving that class its functionality. So really, that class isn't empty. It just doesn't require any extra logic after the decorator is applied to it. bootstrapModule takes a class as input and assumes that that class is decorated with @NgModule configured in a manner similar to what you have (declarations, imports, providers, etc.).