A simple script I use to monitor my RAID setup. It gives a notification if something is wrong.
The terminal command diskutil ar list gives some info about the systems RAIDs.
Since I don't know what the output could look like when something is wrong, I check the occurrences of the word 'Online'.
So if you want to use this script, you have to change that number in the index.js file.
To actually monitor with this thing, I set up a cronjob.