Strange bug using dset with mobx

[filippodossena-mozart]

I noticed that there is a weird bug when using dset with mobx:

dset(data, "a.b.c", 1)

If data is an mobx observable (a deep and proxied one), dset will set only the first key a with an empty object.
The result will be:

{ a: {} }

instead of

{ a: { b: { c: 1 } } }

It happens only when using deep and proxy options in mobx (that are the default options).

Struggling with it, I found out that it is the multiple assignment used in dset function that breaks it.
It can be fixed splitting the multiple assignment into 2 different lines.

I created a sandbox that shows everything I state here (fix included):
https://codesandbox.io/s/dset-mobx-issue-x99gw