TypeError: Cannot read property 'key' of undefined but the object is indeed defined

Forge
1

I have made a sample Forge app that listens to the issue created event on Jira Cloud. This is the code of the function that is called whenever the event happens:

export async function onIssueCreated(event, context) {
	var myIssue = event.issue;
	console.log("issue: " + myIssue);
	console.log("Issue key: " + event.issue.key + ".");
	var issueKey =myIssue.key;
	console.log('Issue created: ' + issueKey + ".");
}

And when an issue is created I get these logs on the Forge tunnel:

INFO    11:40:29.397  ee82e517639665b0  issue: [object Object]
INFO    11:40:29.397  ee82e517639665b0  Issue key: PDM3-5.
ERROR   11:40:29.421  ee82e517639665b0  Cannot read property 'key' of undefined
TypeError: Cannot read property 'key' of undefined
    at onIssueCreated (webpack://product-trigger/src/index.jsx:7)
    at Reference.value (bootstrap.js:1:10087)

It is absolutely contradictory. I know for a fact that the event parameter contains an issue object and that the issue object contains a key property with the key of the issue.
Also, when printing the myIssue variable, the log shows [object Object] which means that the variable is NOT undefined. Then I event try printing the key of the issue directly from event.issue.key and it works!
But when I try to make the assignment var issueKey =myIssue.key; it says that myIssue is undefined. That’s impossible. Could you help me with this? I have never seen anything like this in my whole software developer career.

2

I don’t know where is the issue, but I’ll start by not using var to declare my variables, but the more modern and less error prone const.