LeanAspNetCore.csproj

<Project Sdk="Microsoft.NET.Sdk.Web">

  <PropertyGroup>
    <TargetFramework>netcoreapp2.1</TargetFramework>
    <ClientAppFolder>ClientApp</ClientAppFolder>
  </PropertyGroup>

  <ItemGroup>
    <Folder Include="wwwroot\dist\" />
  </ItemGroup>

  <ItemGroup>
    <PackageReference Include="Microsoft.AspNetCore.App" />
    <PackageReference Include="Microsoft.VisualStudio.Web.CodeGeneration.Design" Version="2.1.0" />
  </ItemGroup>

  <Target Name="EnsureNodeModules" BeforeTargets="Build" Condition=" '$(Configuration)' == 'Debug' And !Exists('$(ClientAppFolder)\node_modules') ">
    <Message Importance="high" Text="Restoring dependencies using 'npm'. This may take several minutes..." />
    <Exec WorkingDirectory="$(ClientAppFolder)" Command="npm install" />
  </Target>
  
  <Target Name="BuildClientAssets" AfterTargets="ComputeFilesToPublish">
    <Exec WorkingDirectory="$(ClientAppFolder)" Command="npm install" />
    <Exec WorkingDirectory="$(ClientAppFolder)" Command="npm run prod" />

    <!-- Include the newly-built files in the publish output -->
    <ItemGroup>
      <DistFiles Include="wwwroot\dist\**" />
      <ResolvedFileToPublish Include="@(DistFiles->'%(FullPath)')" Exclude="@(ResolvedFileToPublish)">
        <RelativePath>%(DistFiles.Identity)</RelativePath>
        <CopyToPublishDirectory>PreserveNewest</CopyToPublishDirectory>
      </ResolvedFileToPublish>
    </ItemGroup>

  </Target>

</Project>