Procedure:
Step1.
Launch a clean Ubuntu18.04, login with default user ubuntu
Step2.
#node -v
v8.10.0
#sudo apt-get update -y
#sudo apt install npm
#sudo npm cache clean -f
#sudo n stable
#node -v
v12.18.3
Step3.
#npm i -g relaxedjs

I know the README tells me not to use sudo but I met permission error so I gotta have a try
#sudo npm i -g relaxedjs


Not sure if there's any prerequisites I miss? Thanks!