NPM run scripts fail when run on Windows

[xtu]

Expected behavior

The code should build without problem and all tests pass when running the commands described in How to reproduce section on Windows platform

Actual behavior

npm run build-browser fails because of setting NODE_ENV environment variable. The syntax does not work on Windows.

npm run build-node fails because mkdir on Windows does not accept -p parameter.

npm test does not work because ; is not treated as command separator on Windows, thus -t 40000 parameter is passed to eslint which is an invalid parameter.

Note: npm install fails only when using npm@4 because it runs prepublish script which executes the build script. In npm@5, npm install does not execute prepublish.

How to reproduce

git clone https://github.com/steemit/steem-js.git
cd steem-jss
npm install
npm run build
npm test

Environment information

Windows 10 Home 64bit node: v8.9.4 npm: v5.6.0 GnuWin32 utilities are in my PATH so I can use gzip and du commands.

Before I upgrade npm to v5.6.0, I was using v4.x, I upgraded to the latest version after I noticed the issue with prepublish being executed by npm install.