Unable to access exception properties in v8 runtime

Question

I am trying to get the stack trace (and other details) when an exception occurs in my code. To do this the following piece of code use to work:

function catchException() {
  
  var errLog = [];
  
  try {
    
    var temp;
    temp.split(",");
    
  } catch (exception) {
    
    for (var property in exception) {
      
      errLog.push(property + ": " + exception[property]);
    }
    
  }
  
  return errLog;
}

But ever since the v8 runtime update on Google Apps Script, this doesn't return any property of the exception object.

In v8 runtime, I can get the stack trace in the above code, if I use exception["stack"], I get the stack trace.

But I was hoping I could avoid using the string ("stack") and also get all the other properties of the exception for which I might not know the property name.

The for...in loop doesn't seem to be working in this scenario.

How can I access the exception object's properties?

(all the properties without using the property names)

Answer 1

for..in only enumerates properties that are configured as enumerable; an exception's "stack" property is not enumerable (you can check with Object.getOwnPropertyDescriptor(exception, "stack")). You can use Object.getOwnPropertyNames to get all property names of an object, enumerable or not:

let keys = Object.getOwnPropertyNames(exception);
for (let key of keys) {
  console.log(key + ": " + exception[key]);
}

Note that, as the name implies, this lists an object's own properties. If you're also interested in properties inherited from its prototypes, you can use a loop to iterate the prototype chain:

function DumpAllProperties(o) {
  let receiver = o;
  while (o) {
    for (let key of Object.getOwnPropertyNames(o)) {
      console.log(key + " -> " + receiver[key]);
    }
    o = Object.getPrototypeOf(o);
  }
}