I have an object that is set using:

// uses jQuery to get form values
setObj = {
 username : $('#username').val(),
 price : $('input[name=price]').val(),
 subject : $('input[name=subject]').val() || $('input[name=ad_title]').val(),
 comment : $('#comment').html() || $('#commentText').val()
};

Later, I check to see if there's data in the object before proceeding. I was using:

if (Object.values(setObj).length > 0) { ... }

but discovered that it ALWAYS succeeds because blank values still count! So the entire form could be empty, but it would still return 4 instead of the expected 0.

Then I was going to use this:

if (setObj.price + setObj.subject + setObj.comment === '') { ... }

but quickly discovered that these could equal "undefinedundefinedundefined", "NaN", or "".

Is there a better way to see if all fields are empty than this?

if (
 // this line can become a real issue if I add more keys later and forget to modify it
 setObj.price + setObj.subject + setObj.comment === 'undefinedundefinedundefined' ||

 setObj.price + setObj.subject + setObj.comment === 'NaN' ||
 setObj.price + setObj.subject + setObj.comment === ''
) { ... }