javascript - Angular 4 SEO-fel

Jag behöver att min app som använder Angular 4 är SEO-vänlig. Jag kom in på den här artikeln för att utföra tricket. https://blog.pusher.com/make-angular-4-app-seo-friendly/

Koden server.ts ser ut så här.

import 'reflect-metadata';
import 'zone.js/dist/zone-node';
import { renderModuleFactory } from '@angular/platform-server';
import { enableProdMode } from '@angular/core';
import * as express from 'express';
import { join } from 'path';
import { readFileSync } from 'fs';
import { AppServerModuleNgFactory } from '../dist/ngfactory/src/app/app-server.module.ngfactory';

enableProdMode();

const PORT     = process.env.PORT || 4000;
const DIST_DIR = join(__dirname, '..', 'dist');
const app = express();
const template = readFileSync(join(DIST_DIR, 'index.html')).toString();

app.engine('html', (_, options, callback) => {
  const newOptions = { document: template, url: options.req.url };

  renderModuleFactory(AppServerModuleNgFactory, newOptions)
    .then(html => callback(null, html));
});

app.set('views', 'src');
app.set('view engine', 'html');

app.get('*.*', express.static(DIST_DIR));
app.get('*', (req, res) => {
  res.render('index', { req });
});

app.listen(PORT, () => {
  console.log(`App listening on http://localhost:${PORT}!`);
});

Då uppstod detta fel när jag körde npm run start som kör "prestart": "ng build --prod && ./node_modules/.bin/ngc", "start": "ts-node src/server.ts",

ERROR in ./src/main.ts
Module not found: Error: Can't resolve './app/app.module.ngfactory' in '/Users/andhika/Documents/Apps/web-yna/src'
resolve './app/app.module.ngfactory' in '/Users/andhika/Documents/Apps/web-yna/src'
  using description file: /Users/andhika/Documents/Apps/web-yna/package.json (relative path: ./src)
    Field 'browser' doesn't contain a valid alias configuration
  after using description file: /Users/andhika/Documents/Apps/web-yna/package.json (relative path: ./src)
    using description file: /Users/andhika/Documents/Apps/web-yna/package.json (relative path: ./src/app/app.module.ngfactory)
      no extension
        Field 'browser' doesn't contain a valid alias configuration
        /Users/andhika/Documents/Apps/web-yna/src/app/app.module.ngfactory doesn't exist
      .ts
        Field 'browser' doesn't contain a valid alias configuration
        /Users/andhika/Documents/Apps/web-yna/src/app/app.module.ngfactory.ts doesn't exist
      .js
        Field 'browser' doesn't contain a valid alias configuration
        /Users/andhika/Documents/Apps/web-yna/src/app/app.module.ngfactory.js doesn't exist
      as directory
        /Users/andhika/Documents/Apps/web-yna/src/app/app.module.ngfactory doesn't exist
[/Users/andhika/Documents/Apps/web-yna/src/app/app.module.ngfactory]
[/Users/andhika/Documents/Apps/web-yna/src/app/app.module.ngfactory.ts]
[/Users/andhika/Documents/Apps/web-yna/src/app/app.module.ngfactory.js]
[/Users/andhika/Documents/Apps/web-yna/src/app/app.module.ngfactory]
 @ ./src/main.ts 3:0-66
 @ multi ./src/main.ts

package.json

{
  "name": "web-yna",
  "version": "0.0.0",
  "license": "MIT",
  "scripts": {
    "ng": "ng",
    "prestart": "ng build dist --prod && ./node_modules/.bin/ngc",
    "start": "ts-node src/server.ts",
    "build": "ng build",
    "test": "ng test",
    "lint": "ng lint",
    "e2e": "ng e2e"
  },
  "private": true,
  "dependencies": {
    "@angular-devkit/build-optimizer": "0.0.35",
    "@angular-devkit/core": "0.0.22",
    "@angular-devkit/schematics": "0.0.41",
    "@angular/animations": "^5.1.0",
    "@angular/common": "^5.1.0",
    "@angular/compiler": "^5.1.0",
    "@angular/core": "^5.1.0",
    "@angular/forms": "^5.1.0",
    "@angular/http": "^5.1.0",
    "@angular/platform-browser": "^5.1.0",
    "@angular/platform-browser-dynamic": "^5.1.0",
    "@angular/platform-server": "^5.1.2",
    "@angular/router": "^5.1.0",
    "@ngtools/json-schema": "^1.1.0",
    "@schematics/angular": "^0.1.10",
    "angularfire2": "^5.0.0-rc.4",
    "bootstrap": "^4.0.0-beta.2",
    "core-js": "^2.5.2",
    "express": "^4.16.2",
    "firebase": "^4.6.2",
    "hammerjs": "^2.0.8",
    "ngx-carousel": "^1.3.5",
    "ngx-parallax": "^2.0.0",
    "ngx-quill": "^2.0.4",
    "path": "^0.12.7",
    "rxjs": "^5.5.5",
    "zone.js": "^0.8.14"
  },
  "devDependencies": {
    "@angular/cli": "1.5.2",
    "@angular/compiler-cli": "^5.1.0",
    "@angular/language-service": "^5.1.0",
    "@types/jasmine": "~2.5.53",
    "@types/jasminewd2": "~2.0.2",
    "@types/node": "~6.0.60",
    "codelyzer": "~3.2.0",
    "jasmine-core": "~2.6.2",
    "jasmine-spec-reporter": "~4.1.0",
    "karma": "~1.7.0",
    "karma-chrome-launcher": "~2.1.1",
    "karma-cli": "~1.0.1",
    "karma-coverage-istanbul-reporter": "^1.2.1",
    "karma-jasmine": "~1.1.0",
    "karma-jasmine-html-reporter": "^0.2.2",
    "protractor": "~5.1.2",
    "ts-node": "~3.2.0",
    "tslint": "~5.7.0",
    "typescript": "~2.4.2"
  }
}

Vänligen rådgör.