NPM脚本"start"退出,但未指示Angular CLI正在侦听请求

Question

我正在尝试启动.NET Core 2/Angular 6 SPA.我使用"dotnet new angular"创建了一个Angular 5应用程序,然后使用angular.io中的本指南进行升级.完成升级后,我尝试使用"dotnet run"运行应用程序,然后出现一个带有错误的丑陋错误页面:

处理请求时发生未处理的异常.

AggregateException:发生一个或多个错误.(发生了一个或多个错误.(NPM脚本'start'退出,但未指示Angular CLI正在侦听请求.错误输出为:Unknown选项:'--extractCss'

InvalidOperationException:NPM脚本'start'退出,但未指示Angular CLI正在侦听请求.错误输出为:未知选项:'--extractCss'

想想也许我在升级过程中错过了一步,我第二次尝试并得到了同样的错误.

以下是我在创建应用后采取的步骤:

npm install -g @angular/cli
npm install @angular/cli
ng update @angular/cli
ng update @angular/core
npm install --save @angular/material @angular/cdk @angular/animations hammerjs 
npm install -g rxjs-tslint
rxjs-5-to-6-migrate -p src/tsconfig.app.json

我在Windows 10(1703)Enterprise上运行Node版本9.4.0和.Net Core 2.1.200.

有想法该怎么解决这个吗？这是一个完整的堆栈跟踪:

 ---> System.IO.EndOfStreamException: Attempted to read past the end of the stream.
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.AspNetCore.SpaServices.AngularCli.AngularCliMiddleware.<StartAngularCliServerAsync>d__3.MoveNext()
   --- End of inner exception stack trace ---
   at Microsoft.AspNetCore.SpaServices.AngularCli.AngularCliMiddleware.<StartAngularCliServerAsync>d__3.MoveNext()
   --- End of inner exception stack trace ---
   at System.Threading.Tasks.Task`1.GetResultCore(Boolean waitCompletionNotification)
   at Microsoft.AspNetCore.SpaServices.AngularCli.AngularCliMiddleware.<>c.<Attach>b__2_0(Task`1 task)
   at System.Threading.Tasks.ContinuationResultTaskFromResultTask`2.InnerInvoke()
   at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
   at System.Threading.Tasks.Task.ExecuteWithThreadLocal(Task& currentTaskSlot)
   --- End of inner exception stack trace ---
   at System.Threading.Tasks.Task`1.GetResultCore(Boolean waitCompletionNotification)
   at Microsoft.AspNetCore.SpaServices.Extensions.Util.TaskTimeoutExtensions.<WithTimeout>d__1`1.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.AspNetCore.SpaServices.Extensions.Proxy.SpaProxy.<PerformProxyRequest>d__4.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.AspNetCore.Builder.SpaProxyingExtensions.<>c__DisplayClass2_0.<<UseProxyToSpaDevelopmentServer>b__0>d.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.AspNetCore.Builder.RouterMiddleware.<Invoke>d__4.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddleware.<Invoke>d__7.MoveNext()
---> (Inner Exception #0) System.AggregateException: One or more errors occurred. (The NPM script 'start' exited without indicating that the Angular CLI was listening for requests. The error output was: Unknown option: '--extractCss'

) ---> System.InvalidOperationException: The NPM script 'start' exited without indicating that the Angular CLI was listening for requests. The error output was: Unknown option: '--extractCss'

 ---> System.IO.EndOfStreamException: Attempted to read past the end of the stream.
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.AspNetCore.SpaServices.AngularCli.AngularCliMiddleware.<StartAngularCliServerAsync>d__3.MoveNext()
   --- End of inner exception stack trace ---
   at Microsoft.AspNetCore.SpaServices.AngularCli.AngularCliMiddleware.<StartAngularCliServerAsync>d__3.MoveNext()
   --- End of inner exception stack trace ---
   at System.Threading.Tasks.Task`1.GetResultCore(Boolean waitCompletionNotification)
   at Microsoft.AspNetCore.SpaServices.AngularCli.AngularCliMiddleware.<>c.<Attach>b__2_0(Task`1 task)
   at System.Threading.Tasks.ContinuationResultTaskFromResultTask`2.InnerInvoke()
   at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
   at System.Threading.Tasks.Task.ExecuteWithThreadLocal(Task& currentTaskSlot)
---> (Inner Exception #0) System.InvalidOperationException: The NPM script 'start' exited without indicating that the Angular CLI was listening for requests. The error output was: Unknown option: '--extractCss'

 ---> System.IO.EndOfStreamException: Attempted to read past the end of the stream.
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.AspNetCore.SpaServices.AngularCli.AngularCliMiddleware.<StartAngularCliServerAsync>d__3.MoveNext()
   --- End of inner exception stack trace ---
   at Microsoft.AspNetCore.SpaServices.AngularCli.AngularCliMiddleware.<StartAngularCliServerAsync>d__3.MoveNext()<---
<---

Answer 1

对我而言,以下问题解决了这个问题:https://github.com/angular/angular-cli/issues/10666

此外,您还需要编辑package.json文件并从start和build属性中删除--extractCss参数.从:

"scripts": {
    "ng": "ng",
    "start": "ng serve --extract-css",
    "build": "ng build --extract-css",

至:

"scripts": {
    "ng": "ng",
    "start": "ng serve",
    "build": "ng build",

Answer 2

尝试执行以下操作

1. 打开Powershell
2. 导航到clientapp目录
3. 运行“ npm审核修复程序”

对我有用

Answer 3

就我而言，我已从azure Web 应用程序中删除了以下应用程序设置，并且站点已开始工作。

键：ASPNETCORE_ENVIRONMENT 值：开发

花了几天时间找出问题:)

Answer 4

这个问题也困扰了我几天.现在终于找到了解决方法.显然,Visual Studio会尝试自动为我们启动Angular CLI服务器以及ASP.Net核心进程.对于这个例子,它失败了.

因此,根据微软的文档在这里,我们可以手动启动角CLI服务器.

1. 导航到"ClientApp"文件夹,然后发出:

   服务

   从控制台启动服务器.

2. 在'Startup.cs'文件中,替换

   spa.UseAngularCliServer(..)

同

spa.UseProxyToSpaDevelopmentServer("http://localhost:4200");

3. F5像往常一样启动ASP.Net Core项目.

这样您就可以继续调试应用程序.