1. 首先，在app.module.ts中添加SwUpdate服务并导入“service-worker-updates”模块。

import { NgModule } from '@angular/core';
import { BrowserModule } from '@angular/platform-browser';
import { AppComponent } from './app.component';
import { environment } from '../environments/environment';
import { ServiceWorkerModule, SwUpdate } from '@angular/service-worker';
import { ServiceWorkerUpdatesModule } from 'service-worker-updates';

@NgModule({
  declarations: [AppComponent],
  imports: [
    BrowserModule,
    ServiceWorkerModule.register('ngsw-worker.js', {
      enabled: environment.production,
    }),
    ServiceWorkerUpdatesModule,
  ],
  providers: [],
  bootstrap: [AppComponent],
})
export class AppModule {
  constructor(private swUpdate: SwUpdate) {
    swUpdate.available.subscribe(event => {
      if (confirm('New version available. Load New Version?')) {
        window.location.reload();
      }
    });
  }
}

2. 确保sw.js文件存在，并且在angular.json文件的“assets”下配置它。

{
  "projects": {
    "your-project-name": {
      "architect": {
        "build": {
          "options": {
            "assets": [
              "src/assets",
              "src/favicon.ico",
              "src/manifest.json",
              "src/sw.js"
            ]
           }
         }
       }
     }
   }
}

3. 确认service-worker.js文件中的self.addEventListener('fetch', event => {});中间没有任何其他代码。

self.addEventListener('fetch', event => {});

通过这些步骤，我们已经将SwUpdate更新提醒和重新加载功能添加到PWA中，而不会导致不必要的更新。