Though rarer in computer science, one can use category theory directly, which defines a monad as a functor with two additional natural transformations. So to begin, a structure requires a higher-order function (or "functional") named map to qualify as a functor:

The central ideas of this design pattern closely mirror the semantics of first-class functions and higher-order functions in functional programming languages. Specifically, the invoker object is a higher-order function of which the command object is a first-class argument.

reduce is a higher-order function which takes two values

However, in this case you would lose the possibility to render something in between. You are strictly coupled to the higher-order component's render method. If you need to add something in between of the currency components, you would have to do it in the higher-order component. It would be quite similar as you have done it previously by rendering the currency components straight away in the Amount component. If using a render prop component instead, you would be flexible in your composition.

For the sake of completeness, the following code demonstrates that the problem could be solved with a higher-order component (HOC) as well: