Fails to transform map argument for redis.msetnx({a:123,b:345})

[garkin]

Fails to transform map argument for redis.msetnx({a:123,b:345})
Somehow related to #217

Before this.initPromise()#:

After:

[luin]

There's no argument transformer for msetnx yet. The built-in ones can be found here: https://github.com/luin/ioredis/blob/master/lib/command.js#L302-L335, and you can define one yourself for msetnx.

However, I think we should have a built-in transformer for msetnx 😆 .

[garkin]

I think it's pretty inconsistent to have msetnx API differ from mset.
Since it should be just an mset with a blackjack.

[luin]

Yes, you're right. Didn't notice this command when I implemented transformers.