If you aren't sure if you have a bash profile yet, run touch ~/.bash_profile (Mac) or touch ~/.bashrc(Linux) to make sure.
Visit https://github.com/creationix/nvm and find a command that looks like this:
curl -o- https://raw.githubusercontent.com/creationix/nvm/v0.31.0/install.sh | bash
Run that command in your terminal. Mac OS might ask you to install some git-related software. You definitely want that.
Visit https://github.com/coreybutler/nvm-windows/releases and click the nvm-setup.zip file associated with the latest release. (1.1.0 at the time this was written).
Extract and run the installer inside of that zip file.
To get Node JS running, you have to install, then activate, a version of Node JS. Here's how:
You might have to restart your terminal after installing NVM. It's important to note that every time you close your terminal, all versions of node get de-activated. See the tip at the bottom of this section to overcome this.
To install the latest version of node:
nvm install node
To install a specific version of node:
nvm install x.x.x (where x.x.x is the version you want).
To activate the latest version of node (assuming it is installed):
nvm use node
To activate a specific version of node (assuming it is installed):
nvm use x.x.x (where x.x.x is the version you want).
Tip: You might want to put a nvm use x.x.x command in your bash profile, so that you don't have to type nvm use x.x.x every time you want to work on a node project. You'll want to add the use command to your .bash_profile file on Mac, or your .bashrc file on Linux.
You might have to restart your command line after installing NVM.
To install the latest version of node:
nvm install latest all (optional: you can change the word all to either 32 or 64 to only install one architecture of node. Adding all tells NVM to install both)
To install a specific version of node:
nvm install x.x.x all (where x.x.x is the version you want)
To activate a specific version of node:
nvm use x.x.x (where x.x.x is the version you want)