We have a Node/NPM build running. Whenever NPM fails, we do get tons of PowerShell error dumps printed to the build log.

Here is an example:

writeErrorStream      : True
PSMessageDetails      : 
Exception             : System.Management.Automation.RemoteException: npm ERR! A complete log of this run can be found in:
                        npm ERR!     C:\Users\appveyor\AppData\Roaming\npm-cache_logs\2018-04-09T12_27_25_603Z-debug.log




TargetObject          : 
CategoryInfo          : NotSpecified: (:) [], RemoteException
FullyQualifiedErrorId : NativeCommandErrorMessage
ErrorDetails          : 
InvocationInfo        : System.Management.Automation.InvocationInfo
ScriptStackTrace      : at <ScriptBlock>, <No file>: line 9
PipelineIterationInfo : {0, 0}
writeErrorStream      : True

Is there any way to turn this off? It duplicates a lot of the NPM output.

Update

I found the issue. We are executing NPM using a PowerShell script like this:

  - ps: |
      ...
      npm run test:without-system-tests
      $NpmTestsExitCode = $LastExitCode
      ...
      # Fail script in case of test failures
      if($NpmTestsExitCode -ne 0) {
        #$Error | Format-List * -Force
        exit $NpmTestsExitCode
      }

The problematic line is: $Error | Format-List * -Force. It seems to dump it to the console (AppVeyor build log). I removed that line and it's good now.