Angular HMR

hmr.ts

import { ApplicationRef, NgModuleRef } from '@angular/core';
import { createNewHosts } from '@angularclass/hmr';
import { ActionReducer } from '@ngrx/store';

export function hmrMetaReducer(reducer: ActionReducer<any>) {
  return (state: any, action: any) =>
    action.type === 'SET_ROOT_STATE'
        ? action.payload
        : reducer(state, action);
}

export const hmrBootstrap = (module: any, bootstrap: () => Promise<NgModuleRef<any>>) => {
  let ngModule: NgModuleRef<any>;
  module.hot.accept();
  bootstrap().then(mod => ngModule = mod);
  module.hot.dispose(() => {
    const appRef: ApplicationRef = ngModule.injector.get(ApplicationRef);
    const elements = appRef.components.map(c => c.location.nativeElement);
    const makeVisible = createNewHosts(elements);
    ngModule.destroy();
    makeVisible();
  });
};

main.ts

import { enableProdMode } from '@angular/core';
import { platformBrowserDynamic } from '@angular/platform-browser-dynamic';

import { hmrBootstrap } from './hmr';

import { AppModule } from './app/app.module';
import { environment } from './environments/environment';

if (environment.production) {
  enableProdMode();
}

const bootstrap = () => platformBrowserDynamic().bootstrapModule(AppModule);

// tslint:disable:no-console
if (!environment.production) {
  if (module['hot']) {
    hmrBootstrap(module, bootstrap);
  } else {
    console.error('HMR is not enabled for webpack-dev-server!');
    console.log('Are you using the --hmr flag for ng serve?');
  }
} else {
  bootstrap().catch(err => console.log(err));
}