About NVM 

A bash shell for node js versions environment & management. 
NVM stands for Node Version Manager. The full github documentation is [here](https://github.com/nvm-sh/nvm). And they have excellent tutorials. 

Another alternative to nvm is simply [n](https://github.com/tj/n). 

```
n latest
```
will install the latest version of javascript. 

You can switch to a different version of node.js by simply entering `n` in the terminal