How to ensure window.onerror to fire for all errors?

Question

I have this simple code at the start of my ts file

//window.onerror = function() {
//    alert('err')
//};

window.addEventListener('error', function (event) {
alert(event.message)
})

As you can see, I've tried both syntaxes.

In another function later on I have:

throw new Error('dummy err');

But the global listener does not fire

What can the issue be?

Chrome shows the the global listener to this line. but nothing happens

I am using React. Though I dont see React to be touching this

How do I ensure that all thrown errors get to my top global handler?

BTW: even regular errors, that are thrown lets say by fetch which get back 500 errors, are also not caught by the global handler. Whats wrong?

Thanks!

Answer 1

As soon as I realized that the errors that were not caught were only from promises / async. I quickly found the answer here https://stackoverflow.com/a/55178672/240742