Fedora 25 Install NPM & NodeJS v6 / v7

NodeJS Installation

curl -sL https://deb.nodesource.com/setup_6.x | sudo -E bash -
sudo apt-get install -y nodejs

https://nodejs.org/en/download/package-manager/

NPM Installation

cd ~
curl -L https://www.npmjs.com/install.sh | sh

Also Fix your permission HERE
https://docs.npmjs.com/getting-started/fixing-npm-permissions