app.module.ts

import { BrowserModule } from '@angular/platform-browser';
import { NgModule } from '@angular/core';

import { AppRoutingModule } from './app-routing.module';
import { AppComponent } from './app.component';
import { ModuleAModule } from './moduleA/moduleA.module';


@NgModule({
  declarations: [
    AppComponent
  ],
  imports: [
    BrowserModule,
    AppRoutingModule,
    ModuleAModule.forRoot(),
  ],
  bootstrap: [AppComponent]
})
export class AppModule { }

moduleB.module.ts

import { NgModule } from '@angular/core';
import { ModuleAModule } from '../moduleA/moduleA.module';

import { ModuleBComponent } from './moduleB.component';
import { ModuleBRoutingModule } from './moduleB.routing.module';


@NgModule({
  declarations: [
    ModuleBComponent,
  ],
  imports: [
    ModuleAModule.forChild(),
    ModuleBRoutingModule,
  ],
})
export class ModuleBModule { }