deepEqual: returns true comparing empty object with empty class instance

[mgred]

@tbiesemann opened in sinon sinonjs/sinon#1882

it("passes instance and object", function() {
    var obj = {};
    var ins = new (class MyClass {});
    assert.isFalse(samsam.deepEqual(obj, ins));
});

• library version : 2.0.0
• Environment : nodejs

What did you expect to happen?

It should return false.

What actually happens

It fails the test and returns true

Solution

As suggested by @tbiesemann, compare the names of the constructors:

if (
    type1 !== type2 ||
    class1 !== class2 ||
    obj1.constructor.name !== obj2.constructor.name ||
    keys1.length !== keys2.length
) {
    return false;
}

https://github.com/sinonjs/samsam/blob/master/lib/deep-equal.js#L105

Note: This modification lets the mentioned test pass but lets tests crash that pass objects that have no prototype.
I will provide a PR for this