How to find an expression in source and use it inside IF clause

I am getting the html source into a variable but then I could not find a way to check a special keyword exists in the source code or not.

I want to do something like that:
StoreHtmlSource → src
if(src.contains(‘keyword x’)) then …

How can we do that in the recorder? I am using Katalon Automation Recorder 3.5.6 inside Chrome.