How can I completely uninstall nodejs, npm and node in Ubuntu

sudo apt-get remove nodejs
sudo apt-get remove npm

Then go to /etc/apt/sources.list.d and remove any node list if you have. Then do a

sudo apt-get update

Check for any .npm or .node folder in your home folder and delete those.

If you type

which node

you can see the location of the node. Try which nodejs and which npm too.

I would recommend installing node using Node Version Manager(NVM). That saved a lot of headache for me. You can install nodejs and npm without sudo using nvm.

It is better to remove NodeJS and its modules manually because installation leaves a lot of files, links and modules behind and later this creates problems when we reconfigure another version of NodeJS and its modules.

To remove the files, run the following commands:

sudo rm -rf /usr/local/bin/npm 
sudo rm -rf /usr/local/share/man/man1/node* 
sudo rm -rf /usr/local/lib/dtrace/node.d
rm -rf ~/.npm
rm -rf ~/.node-gyp
sudo rm -rf /opt/local/bin/node
sudo rm -rf /opt/local/include/node
sudo rm -rf /opt/local/lib/node_modules
sudo rm -rf /usr/local/lib/node*
sudo rm -rf /usr/local/include/node*
sudo rm -rf /usr/local/bin/node*

I have posted a step by step guide with commands on my blog: AMCOS IT Support For Windows and Linux: To completely uninstall node js from Ubuntu.