Angular 2 Nesting modules


Modules can be nested by using the imports parameter of @NgModule decorator.

We can create a core.module in our application that will contain generic things, like a ReservePipe (a pipe that reverse a string) and bundle those in this module:

import { CommonModule } from '@angular/common';
import { NgModule } from '@angular/core';
import { ReversePipe } from '../reverse.pipe';

  imports: [
  exports: [ReversePipe], // export things to be imported in another module
  declarations: [ReversePipe],
export class CoreModule { }

Then in the app.module:

import { CoreModule } from 'app/core/core.module';

  declarations: [...], // ReversePipe is available without declaring here
                       // because CoreModule exports it
  imports: [
    CoreModule,        // import things from CoreModule
  providers: [],
  bootstrap: [AppComponent]
export class AppModule { }