Add a config option for unhandledrejection behavior

[raycohen]

I have a large codebase with tests written with QUnit 1. While upgrading, a lot of them fail with QUnit 2.5 because it started considering unhandled rejections errors.

I can probably find a way to work around this, but I was wondering if the QUnit project would support a config option to go back to the old way of allowing unhandled rejections?

[rwjblue]

I'm definitely sympathetic to your situation, but I don't think we should have divergent behavior (between window.onerror handling and window.onunhandledRejection handling) here.

FWIW, as a work around while you work on fixing your test suite you should be able to do something like:

const KNOWN_REJECTIONS = [
  // list of known rejections in your test suite
  // as issues are fixed, you should remove entries
  // from this array
  //
  // the goal here is to ensure that no **knew** unhandled
  // rejections get added to the test suite, while the existing
  // ones are whittled away
];
const ORIG_QUNIT_UNHANDLED_REJECTION = QUnit.onUnhandledRejection;
QUnit.onUnhandledRejection = function(reason) {
  if (KNOWN_REJECTIONS.indexOf(reason.message) > -1) {
    // do nothing
  } else {
    return ORIG_QUNIT_UNHANDLED_REJECTION.call(QUnit, reason);
  }
};

This works because QUnit sets up a handler for the event that calls the QUnit.onUnhandledRejection method:

qunit/reporter/html.js

Lines 1059 to 1061 in d7f1e27

	window.addEventListener( "unhandledrejection", function( event ) {
	QUnit.onUnhandledRejection( event.reason );
	} );

[raycohen]

No problem. Thanks for the workaround suggestion!

[NullVoxPopuli]

properties on QUnit are read-only, so this approach is no longer viable.