The SPA application is using a newer version of NPM than the one provided by Visual Studio 2015 (npm 2.7.4 currently), so you need to install the latest stable version of NPM,like npm .
NPM is bundled with NODE.JS. Installing NPM and NODE is pretty straightforward by using the installer package available at https://nodejs.org/en/
You can install the version "Recommended For Most Users" of Node which at the moment of this writing was v6.9.3 LTS and comes with a newer version of NPM.
You can see your initial NPM version and the installed NPM version with the command
If you get an error like <b>"Node Sass could not find a binding for your current environment: Windows 64-bit with Node.js 6.x"</b>, then run the command <b>npm rebuild node-sass</b> as in the following screenshot:
Create the Docker images with the <b>build-images.ps1</b> PowerShell script in Windows (or the <b>build-images.sh</b> bash script in a Mac) as explained in the main instructions at https://github.com/dotnet/eShopOnContainers/