What are immutable types?
These are types that you can instantiate but never mutate the values. In order to update a value, you must instantiate a new value.
Why using immutable types?
Properties, like in React, are propagated from ancestors to
children. This means that the properties must live when each component is
updated. This is why properties should —ideally— be cheap to clone. To
achieve this we usually wrap things in
Immutable types are a great fit for holding property's values because they can be cheaply cloned when passed from component to component.