Install node.js binaries

1. Download the node.js binaries here:
   https://nodejs.org/en/download/
2. Extract the file:
   $ tar xvf node-v8.10.0-linux-armv7l.tar.xz
3. (optional) Move the binaries to target path:
   $ move node-v8.10.0-linux-armv7l /usr/local/lib/nodejs/
4. Set path in ~/.profile
   # Nodejs
   export NODEJS_HOME=/usr/local/lib/nodejs/node-v8.10.0
   export PATH=$NODEJS_HOME/bin:$PATH

Now source .profile, mkdir nodejs_test, npm init should create package.json. You can try 

$ npm install express -save

to see if npm is working properly.