Check when the last Time Machine Backup was and display notification

tm-check.js

// use it in calender: http://apple.stackexchange.com/a/59265/14030
app = Application.currentApplication()
app.includeStandardAdditions = true

ObjC.import('Cocoa')
dict = $.NSDictionary.dictionaryWithContentsOfFile('/Library/Preferences/com.apple.TimeMachine.plist')
firstItem = dict.valueForKey('Destinations').firstObject
lastBackup = firstItem.valueForKey('SnapshotDates').lastObject

diff = lastBackup.timeIntervalSinceNow // in seconds
diff = (diff * -1)

if (diff > 60*60*24*3) {
	app.displayNotification('Last Backup is more than 3 days old.' ) //, {withTitle: 'BACKUP'}
}