ActiveRecord::Base.normalizes declares an attribute normalization. The normalization is applied when the attribute is assigned or updated, and the normalized value will be persisted to the database. The normalization is also applied to the corresponding keyword argument of query methods, allowing records to be queried using unnormalized values.

What I have seen is situations where things were made horribly complicated to get around protections for which there was no need, and to try to guard the consistency of data structures that were horribly over-complicated and un-normalized.

Far more preferable is to minimize data structure so that it tends to be normalized and not to have inconsistent states. Then, if a member of a class is changed, it is simply changed, rather than damaged.

With MobX you don't need to normalize your data.