Raygun ignores Syntax errors during page loading when `ignore3rdPartyErrors` enabled

[Obi-Dann]

Hello,

I have ignore3rdPartyErrors enabled to reduce the noise from browser extensions, but it also prevents errors caught during the initial JS bundle loading to be ignored.
Before rg4js is loaded, it attaches a handler to window.onError, but it ignores every bit of useful information there only using the value of msg which is just a string that does not have any stack trace.

raygun4js/src/umd.intro.js

Lines 22 to 33 in a3f9b66

	windw.onerror = function (msg, url, line, col, err) {
	if (originalOnError) {
	originalOnError(msg, url, line, col, err);
	}
	if (!err) {
	err = new Error(msg);
	}
	windw['rg4js'].q = windw['rg4js'].q || [];
	windw['rg4js'].q.push({e: err});
	};

Because the error does not have stack trace, it gets ignored by ignore3rdPartyErrors.

Possible solution would be to extend that error with other data from onError like line number, filename etc and stop that error from being ignored by ignore3rdPartyErrors

[BenjaminHarding]

Thanks for filing the issue @Obi-Dann.

I can see how what you are describing could occur but from my understanding it would only happen if the onerror event doesn't provide a Error object. Upon which we then instantiate our own Error instance, which could be missing that information.

Not saying it's not a case we should not cater towards, but that I'd like to first know (or remember) when that object is not available :)

[Obi-Dann]

I narrowed it down to SyntaxErrors. When SyntaxError is thrown, onerror has the error object but it's quite useless - there's no stack and hardly any useful information in the error object. Other parameters on the other hand have lots of useful info: filename, lineno and colno all populated with correct details.
I wonder if SyntaxErrors should be treated differently in onerror handler.
Going to experiment a bit more and see if I can come up with a simple solution

[BenjaminHarding]

Interesting findings @Obi-Dann! I'll be interested in what you find out :)