install latest node & npm (see https://github.com/sdesalas/node-pi-zero)
or https://www.thepolyglotdeveloper.com/2018/03/install-nodejs-raspberry-pi-zero-w-nodesource/
wget -O - https://raw.githubusercontent.com/sdesalas/node-pi-zero/master/install-node-v.last.sh | bash