For you to run any NodeJS app in any environment(folder). Do the following
Install the app globally
npm install uglify-js -g
Exit and re-open the command prompt
Run uglifyJS without node command
uglifyjs [options] filename
You can run it by :
node C:\gitrepos\uglifyjs\bin\uglifyjs -o inputfile.min.js inputfile.js
You could just add the C:\gitrepos\uglifyjs\bin path to your...path environment variable.