peertube/client/src/app/app.module.ts

import { ApplicationRef, NgModule } from '@angular/core';
import { BrowserModule } from '@angular/platform-browser';
import {
  removeNgStyles,
  createNewHosts,
  createInputTransfer
} from '@angularclass/hmr';

import { MetaModule, MetaLoader, MetaStaticLoader, PageTitlePositioning } from '@nglibs/meta';
// TODO: remove, we need this to avoid error in ng2-smart-table
import 'rxjs/add/operator/toPromise';
import 'bootstrap-loader';

import { ENV_PROVIDERS } from './environment';
import { AppRoutingModule } from './app-routing.module';
import { AppComponent } from './app.component';
import { AppState, InternalStateType } from './app.service';

import { AccountModule } from './account';
import { CoreModule } from './core';
import { LoginModule } from './login';
import { SignupModule } from './signup';
import { SharedModule } from './shared';
import { VideosModule } from './videos';

export function metaFactory(): MetaLoader {
  return new MetaStaticLoader({
    pageTitlePositioning: PageTitlePositioning.PrependPageTitle,
    pageTitleSeparator: ' - ',
    applicationName: 'PeerTube',
    defaults: {
      title: 'PeerTube',
      description: 'PeerTube, a decentralized video streaming platform using P2P (BitTorrent) directly in the web browser'
    }
  });
}

type StoreType = {
  state: InternalStateType,
  restoreInputValues: () => void,
  disposeOldHosts: () => void
};

// Application wide providers
const APP_PROVIDERS = [
  AppState
];

@NgModule({
  bootstrap: [ AppComponent ],
  declarations: [
    AppComponent
  ],
  imports: [
    BrowserModule,

    CoreModule,
    SharedModule,

    AppRoutingModule,

    AccountModule,
    CoreModule,
    LoginModule,
    SignupModule,
    SharedModule,
    VideosModule,

    MetaModule.forRoot({
      provide: MetaLoader,
      useFactory: (metaFactory)
    })
  ],
  providers: [ // expose our Services and Providers into Angular's dependency injection
    ENV_PROVIDERS,
    APP_PROVIDERS
  ]
})
export class AppModule {
  constructor(
    public appRef: ApplicationRef,
    public appState: AppState
  ) {}

  public hmrOnInit(store: StoreType) {
    if (!store || !store.state) {
      return;
    }
    console.log('HMR store', JSON.stringify(store, null, 2));
    /**
     * Set state
     */
    this.appState._state = store.state;
    /**
     * Set input values
     */
    if ('restoreInputValues' in store) {
      let restoreInputValues = store.restoreInputValues;
      setTimeout(restoreInputValues);
    }

    this.appRef.tick();
    delete store.state;
    delete store.restoreInputValues;
  }

  public hmrOnDestroy(store: StoreType) {
    const cmpLocation = this.appRef.components.map((cmp) => cmp.location.nativeElement);
    /**
     * Save state
     */
    const state = this.appState._state;
    store.state = state;
    /**
     * Recreate root elements
     */
    store.disposeOldHosts = createNewHosts(cmpLocation);
    /**
     * Save input values
     */
    store.restoreInputValues  = createInputTransfer();
    /**
     * Remove styles
     */
    removeNgStyles();
  }

  public hmrAfterDestroy(store: StoreType) {
    /**
     * Display new elements
     */
    store.disposeOldHosts();
    delete store.disposeOldHosts;
  }
}