Error when updating state from null to an object.

[Kanaye]

When updating a states property from a primitiv value (e.g. null) null to an object.
The following line tries to access an property on the primitiv value and therefore throws an error.

stockroom/src/util.js

Line 52 in 0c99699

update[i] = diffOne(obj[i], prev[i]);

Here an example.

I probably also PR for this one later.

Edit: It's only null because typeof null === 'object'.