(ripped/converted from dominictarr/my-local-ip)
get the netmask of your current ip address' on the local-network
console.log(require('my-local-netmask')())
//==> 255.255.255.0
Also, because sometime you need this (cross-platform!)
> npm install -g my-local-netmask
> my-local-netmask
255.255.255.0
MIT