Postman: How to check whether the field is returning null in the Postman automation

Question

I have tried with \"!== null\", but it is returning PASS even when the field is returning 0 or \"\".

Answer 1

If you are checking the Id of the first item returned in a list, you could use not.equal(null):

pm.expect(pm.response.json().value[0].Id).not.equal(null);

Note that the word "equal" is fully spelled out, although the shortened "eql" does work.