Installing nodejs

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

updated:
I just installed nodejs and npm in a newly created vm.

sudo apt-get update
sudo apt-get install nodejs

sudo apt-get install npm

https://www.digitalocean.com/community/tutorials/how-to-install-node-js-on-ubuntu-16-04



update: 7/30/2018
Alternatively, for Node.js 10:

curl -sL https://deb.nodesource.com/setup_10.x | sudo -E bash - 

sudo apt-get install -y nodejs