Adopted from here https://topaxi.codes/use-npm-without-root-or-sudo-rights/
I'm saving this as a gist and modifying it to ensure that if the original blog post disappears it lives on somewhere.
Added some notes for Ubuntu 18.04 and similar.
Today we're going to setup our npm installation to be used without root or sudo rights.
By default, if you install packages globally with npm, npm tries to install them into a system directory (i.e. /usr/local/lib/node_modules). With the next steps, we're going to use your home directory for those files.