Node JS, run same function after it is finished

My applications need to poll every 2 seconds if there are changes. For now i use setInterval, but sometimes myFunction takes longer then 2 seconds to execute and records in the mysql database will be inserted twice. I make use of the async lib in myFunction..

So i need this...

When myFunction is finished

method.myFunction() =>

It needs to run again (but only when it is finished). setInterval with x seconds is not an option. This is because they can run at the same time if the scripts takes longer then x seconds.

How can i run myFunction again after x seconds, but only when myFunction is done with processing So in psuedo code it would be this

if method.myFunction == finished wait 2 seconds run method.myFunction again

via erwinnandpersad