How to check if response in certain format?

William

I have an external api that return object as { "error":"abc"} if the request occurs and the actual json if there is a result. 

How do I check is "error" is returned? I see that there no filter called isDefined or something like that? Can you help?  

Michael Udinski

 I might just add a Conditional and say something like 

WHERE

var: your_response
| GET |
path: error
default: null

Does not equal

null

THEN
whatever logic you need if the error is in the object.