The apt-get version of node is incredibly old, and installing a new copy is a bit of a runaround.
So here's how you can use NVM to quickly get a fresh copy of Node on your new Bash on Windows install
//switch to root
$ sudo su
//get NVM
$ curl -o- https://raw.githubusercontent.com/nvm-sh/nvm/v0.35.3/install.sh | bash
$ nvm --version
0.35.3
// Close and reopen your terminal to start using nvm or run the following to use it now:
$ export NVM_DIR="$HOME/.nvm"
[ -s "$NVM_DIR/nvm.sh" ] && \. "$NVM_DIR/nvm.sh" # This loads nvm
[ -s "$NVM_DIR/bash_completion" ] && \. "$NVM_DIR/bash_completion" # This loads nvm bash_completion
//python3-distutils is a required dep see more at [link](https://github.com/nodejs/node/issues/30189)
$ apt install python3-distutils -y
// to install latest version use 'node' instead '--lts'
$ nvm install --lts
Once you've done that you'll get a nice:
$ node --version
$ v12.18.3