It would be convenient if assert.rejects() and assert.throws() returned the error value.

When a more complex assertion is needed, I find the matcher callback to be a bit awkward, especially if the rest of the test code uses await and can mostly avoid nested callbacks. It would also make tests that check success and error cases more similar to each other.

Basically, I would like to be able to write tests like this:

QUnit.test('getResultAsync (OK)', async (assert) => {
    let result = await getResultAsync('foo');
    assert.true(result instanceof MyResult)
    assert.strictEqual(result.value, 'FOO');
});

QUnit.test('getResultAsync (error, proposed API)', async (assert) => {
    let error = await assert.rejects(getResultAsync(''));
    assert.true(error instanceof MyError)
    assert.strictEqual(error.errorCode, 'empty-param');
});

Here's a runnable demo with some more examples, and the alternatives possible using the currently existing API.
test.html

This could be implemented by just adding return actual; at the end of the throws and rejects functions in https://github.com/qunitjs/qunit/blob/main/src/core/assert.js.