在localhost：3000上启动npm后，控制台显示错误

在localhost：3000上单击npm start后，我在控制台日志中收到以下错误

不能GET / @angular度/平台浏览器dynamic

npm版本3.10.9节点版本v7.2.0

package.json如下

{ "name": "angular-quickstart", "version": "1.0.0", "description": "QuickStart package.json from the documentation, supplemented with testing support", "scripts": { "build": "tsc -p src/", "build:watch": "tsc -p src/ -w", "build:e2e": "tsc -p e2e/", "serve": "lite-server -c=bs-config.json", "serve:e2e": "lite-server -c=bs-config.e2e.json", "prestart": "npm run build", "start": "concurrently \"npm run build:watch\" \"npm run serve\"", "pree2e": "npm run build:e2e", "e2e": "concurrently \"npm run serve:e2e\" \"npm run protractor\" --kill-others --success first", "preprotractor": "webdriver-manager update", "protractor": "protractor protractor.config.js", "pretest": "npm run build", "test": "concurrently \"npm run build:watch\" \"karma start karma.conf.js\"", "pretest:once": "npm run build", "test:once": "karma start karma.conf.js --single-run", "lint": "tslint ./src/**/*.ts -t verbose" }, "keywords": [], "author": "", "license": "MIT", "dependencies": { "@angular/common": "~4.0.0", "@angular/compiler": "~4.0.0", "@angular/core": "~4.0.0", "@angular/forms": "~4.0.0", "@angular/http": "~4.0.0", "@angular/material": "^2.0.0-beta.3", "@angular/platform-browser": "~4.0.0", "@angular/platform-browser-dynamic": "~4.1.3", "@angular/router": "~4.0.0", "angular-in-memory-web-api": "~0.3.0", "core-js": "^2.4.1", "rxjs": "5.0.1", "systemjs": "0.19.40", "zone.js": "^0.8.4" }, "devDependencies": { "concurrently": "^3.2.0", "lite-server": "^2.2.2", "typescript": "~2.1.0", "canonical-path": "0.0.2", "tslint": "^3.15.1", "lodash": "^4.16.4", "jasmine-core": "~2.4.1", "karma": "^1.3.0", "karma-chrome-launcher": "^2.0.0", "karma-cli": "^1.0.1", "karma-jasmine": "^1.0.2", "karma-jasmine-html-reporter": "^0.2.2", "protractor": "~4.0.14", "rimraf": "^2.5.4", "@types/node": "^6.0.46", "@types/jasmine": "2.5.36" }, "repository": {} }

app.module.ts如下

 import { NgModule } from '@angular/core'; import { BrowserModule } from '@angular/platform-browser'; import { MaterialModule } from '@angular/material'; import { AppComponent } from './app.component'; @NgModule({ imports: [ BrowserModule, MaterialModule ], declarations: [ AppComponent ], bootstrap: [ AppComponent ] }) export class AppModule { }

Main.ts

 import { platformBrowserDynamic } from '@angular/platform-browser-dynamic'; import { AppModule } from './app/app.module'; platformBrowserDynamic().bootstrapModule(AppModule);

为什么应用程序无法在node_modules下载入platform-browser-dynamic？我validation文件存在指定的文件夹下，仍然收到此错误。