So Switches are slightly different than Decisions or If statements. The Cases should equal an Integer or String that the Expression returns (if that makes sense). The Expression should return exactly the string you are going to use as your Case so for example “facebook”.
In order to use .Contains, you can simply put that in the Expression. For example,
Expression: If( row("URL").ToString.ToUpper.Contains("FACEBOOK"), "facebook", If( row("URL").ToString.ToUpper.Contains("TWITTER"), "twitter", "default" )
Then your cases would just look like:
I would also recommend using this in a Flow Chart, but that’s my opinion.
You can also consider State Machines. They allow you to use a full condition for the destination of each platform, that is, if each one uses a different process.