Assertion error does not state problematic parts for Maps

chai.expect(new Map([['a','a']])).to.deep.equal(new Map([['a','b']]))
// AssertionError: expected {} to deeply equal {}

As you can see it is not clear why it fails from the error message.

[pcorpet]

I’ve created a PR, please help me there to understand which changes are OK, and which ones are not

[flaambe]

I tried to integrate the loup into chai, but unfortunately now I do not have enough time for this