How to inherit a module from another module in Angular2?

Question

So I'm using Angular 2 final (2.0.0) and let's say i create a WidgetsModule with a bunch of directives and components that will help me build my application, and then import it in my AppModule

import { NgModule }      from '@angular/core';
import { UniversalModule } from 'angular2-universal';

import { WidgetsModule } from '../../../widgets';
import { App, appRouting } from './';

@NgModule({
  imports:      [
    UniversalModule,
    WidgetsModule,
    appRouting
  ],
  providers:    [ AppPresenter ],
  declarations: [ App ],
  exports:      [ ],
  bootstrap:    [ App ]
})
export class AppModule { }

Then i want to use widgets in the child modules, like HomeModule, CartModule, etc. How can I make the widgets available without having to import the WidgetsModule in every other Module?

import { NgModule }      from '@angular/core';
import { CommonModule } from '@angular/common';
import { FormsModule, ReactiveFormsModule } from '@angular/forms'

import { WidgetsModule } from '../../../widgets';
import { Cart, cartRouting } from './';

@NgModule({
  imports:      [
    CommonModule,
    FormsModule,
    ReactiveFormsModule,
    WidgetsModule,  //<-- I want to avoid doing this in every module
    cartRouting
  ],
  providers:    [ ],
  declarations: [ Cart ]

})
export class CartModule { }

Is there a way to do it like it's done with the directives in the exports[]?

Answer 1

It directly needs access to its own WidgetsModule just like it need direct access to it's own FormsModule (one way or another). One way to clean it up though is to export all the modules that are used in multiple places, from a SharedModule. Then you can just import the SharedModule everywhere

@NgModule({
  exports: [
    FormsModule,
    CommonModule,
    WidgetsModule
  ]
})
class SharedModule {}

You don't need to imports any of them into the SharedModule unless say you are declaring a component in the SharedModule that uses any of those other modules.

Then in all your other modules, just imports the SharedModule. This ends up cleaning it up a lot, and you only need to maintain one shared module.

See Also:

• Angular2 How to clean up the AppModule