main.ts

import { enableProdMode, ViewEncapsulation } from '@angular/core';
import { platformBrowserDynamic } from '@angular/platform-browser-dynamic';
import { AppModule } from 'app/app.module';
import { environment } from '@env/environment';
import { preloaderFinished } from '@delon/theme';
preloaderFinished();
import { hmrBootstrap } from 'hmr';

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

const bootstrap = () => {
    return platformBrowserDynamic()
        .bootstrapModule(AppModule, {
            defaultEncapsulation: ViewEncapsulation.Emulated,
            preserveWhitespaces: false,
        })
        .then(res => {
            if ((<any>window).appBootstrap) {
                (<any>window).appBootstrap();
            }
            return res;
        });
};

if (environment.hmr) {
    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();
}