Update array on bind (issue #19)

[lunardog]

$bindAsArray fails to update if used after $unbind on the same key. Array items arrive from Firebase, but the property doesn’t show change, array looks empty.

Use case: same Vue component changes its reference during its lifetime.

[lunardog]

Suddenly, I'm having an "infinite watch" warning in my project. Could it be caused by the $delete?

[harrysbaraini]

@lunardog I am using your changes on my project, and I was having "infinite watch" too, but I found I was returning a value in my "watch" function.

[lunardog]

I think there's a danger to the use case I suggested: when we re-bind, the events stay. I added the delete on the reactive prop, but not on the firebase events for value and child_*.

Reject?

[posva]

I'm taking a look into this. There's actually an easier way than deleting the key using Vue.delete, I'll post a PR with more tests for it. I hope you don't mind I pick your test and modify it a bit 😄

[lunardog]

No problem, @posva. Thank you for taking care of this. I see you check if vm[key] is undefined before binding. That is indeed more elegant.

I'll close this PR.