Extend R.apex

It is your personal preference to choose between functional composition and function chaining. And the key takeaway is to use whatever is suitable in your case.

It is sad that the discovery of R.apex almost comes to an end. Realizing that the functions provided by R.apex is limited, you have to come up with your functions to tackle all the difficult business logic. The suggestion will be to encapsulate your core business logic in small custom functions and glue them together with the power of R.apex to build your own application. And this is the way you extend R.apex.