Immutable React

Redux is a small library that represents state as (immutable) objects . And new states by passing the current state through pure functions to create an entirely new object/application states.

In Angular apps, the immutability term is mostly mentioned when you deal with the OnPush change detection strategy. Mutable update patterns may not only prevent you from taking advantage of narrowing a components tree subjected to the change detection, but it also leads to hard to spot bugs/gotchas .

Immutable state means its value cannot be changed once it’s created . That’s it. You might be a bit concerned by this, after all, why would I use a state that can’t be modified? Normally, it isn’t possible to create a good user experience if we don’t allow users to update the data they create.