my angular 7 PWA can't found file 'ngsw.json' when is offline

Question

I am doing a PWA aplication and it works well (Pass al the audits of Chorme) but when i want to try it in offline mode. a 504 TIMEOUT error appears. The DevsTools(Chorme) shows 'An unknown error occurred when fetching the script, Failed to load resource: net::ERR_INTERNET_DISCONNECTED' and Network slice shows a failed when the app try to get "ngsw.json?ngsw-cache-bust=0.30493506524068925"

This is my package:

{
  "name": "avl",
  "version": "0.0.0",
  "scripts": {
    "ng": "ng",
    "start": "ng serve",
    "build": "ng build",
    "test": "ng test",
    "lint": "ng lint",
    "e2e": "ng e2e"
  },
  "private": true,
  "dependencies": {
    "@angular/animations": "^7.2.8",
    "@angular/cdk": "^7.3.4",
    "@angular/common": "~7.2.0",
    "@angular/compiler": "~7.2.0",
    "@angular/core": "~7.2.0",
    "@angular/flex-layout": "^7.0.0-beta.24",
    "@angular/forms": "~7.2.0",
    "@angular/http": "^7.2.8",
    "@angular/material": "^7.3.4",
    "@angular/platform-browser": "~7.2.0",
    "@angular/platform-browser-dynamic": "~7.2.0",
    "@angular/pwa": "^0.13.8",
    "@angular/router": "~7.2.0",
    "@angular/service-worker": "^7.2.13",
    "@mapbox/leaflet-pip": "^1.1.0",
    "@types/fontfaceobserver": "^0.0.6",
    "@types/leaflet": "^1.4.3",
    "@types/pixi.js": "4.7.2",
    "cerialize": "^0.1.18",
    "core-js": "^2.5.4",
    "fontfaceobserver": "^2.1.0",
    "leaflet-pixi-overlay": "^1.6.0",
    "moment": "^2.24.0",
    "net": "^1.0.2",
    "pixi.js": "4.7.2",
    "rxjs": "~6.3.3",
    "rxjs-compat": "6.3.3",
    "tslib": "^1.9.0",
    "wellknown": "^0.5.0",
    "zone.js": "~0.8.26"
  },
  "devDependencies": {
    "@angular-devkit/build-angular": "^0.13.7",
    "@angular/cli": "~7.3.3",
    "@angular/compiler-cli": "~7.2.0",
    "@angular/language-service": "^7.2.8",
    "@types/jasmine": "~2.8.8",
    "@types/jasminewd2": "~2.0.3",
    "@types/node": "~8.9.4",
    "codelyzer": "~4.5.0",
    "jasmine-core": "~2.99.1",
    "jasmine-spec-reporter": "~4.2.1",
    "karma": "~4.0.0",
    "karma-chrome-launcher": "~2.2.0",
    "karma-coverage-istanbul-reporter": "~2.0.1",
    "karma-jasmine": "~1.1.2",
    "karma-jasmine-html-reporter": "^0.2.2",
    "protractor": "~5.4.0",
    "ts-node": "~7.0.0",
    "tslint": "~5.11.0",
    "typescript": "~3.2.2"
  }
}

this is my ngsw-config.json

{
  "index": "/index.html",
  "assetGroups": [
    {
      "name": "app",
      "installMode": "prefetch",
      "resources": {
        "files": [
          "/favicon.ico",
          "/index.html",
          "/*.css",
          "/*.js",
          "/*.json"
        ]
      }
    }, {
      "name": "assets",
      "installMode": "lazy",
      "updateMode": "prefetch",
      "resources": {
        "files": [
          "/assets/**",
          "/*.(eot|svg|cur|jpg|png|webp|gif|otf|ttf|woff|woff2|ani|json)"
        ]
      }
    }
  ]
}

I expect to see the html of the app with his css

Answer 1

The web manifest looks correct to me.

Service workers do not work with ng serve. So you have to do a prod build (ng build --prod) ans serve the compiled code locally with a web server.

In order to verify if your service worker has been correctly installed and it is running:

• Open Chrome Dev Tools
• Access the "Application" Tab
• Click on "Service Worker" link (on the left side)

If the service worker is running, it will be displayed there.

I wrote a step by step guide for creating an Angular PWA (there is also a final DEMO on Github), maybe you can follow it along and see if anything is missing.