toThrowError doesn't consider inheritance

[chge]

toThrowError is very useful, but I think it works incorrectly with custom error classes.

function PirateError(message) {
    this.message = 'Arrggghhhh! ' + message;
}
PirateError.prototype = new Error();

describe('custom try/catch', function() {
    it('works fine in tests', function() {
        try {
            throw new PirateError();
        } catch (error) {
            expect(error).toEqual(jasmine.any(Error));
            expect(error).toEqual(jasmine.any(PirateError));
            expect(error instanceof Error).toBeTruthy();
            expect(error instanceof PirateError).toBeTruthy();
        }
    });
});

describe('toThrowError', function() {
    it('considers error inheritance', function() {
        expect(function() {
            throw new PirateError('Blow me down!');
        }).toThrowError(PirateError);
    });
});

Result:

Expected function to throw PirateError, but it threw Error.

[slackersoft]

Jasmine uses the constructor attribute to determine whether the thrown error is of the desired type. When you assign the prototype of your PirateError to be a new Error() it changes the constructor to the Error function instead. If you add:

PirateError.prototype.constructor = PirateError;

after you assign the prototype your example should work.

We'd be open to a way to do this checking that didn't require re-assigning the constructor after setting the prototype, but none has come up yet.

[chge]

But, for example, jasmine.any uses instanceof for matching. Why shouldn't toThrowError use instanceof instead of direct constructor comparison?