I’d look into using a snippet. I typically looked to see which parameters I receive and then figure out if it’s a go.

Is there any way to achieve it by declarative approach?
If No, can you tell me how to access chart’s series data inside JS snippet?

Almost certain there isn’t.

Could you help me on how to access chart’s series data inside JS snippet?

Sure. Create a snippet with the following:

var params = arguments[0],
$ = skuid.$;

console.log(params);

Then in the console you’ll be able to review what you get as parameters and subsequently update your condition as required. Giving you any more than this I’d have to charge you for it.