Your example shows that it is possible to give NAMES to the intermediate results of a long chain. Giving names to things makes it easier to understand the inte

Your example shows that it is possible to give NAMES to the intermediate results of a long chain. Giving names to things makes it easier to understand the intention of the programmer. And that also allows you to create a TREE of dataflow-code not just a CHAIN. For instance 'longBooks' could be used as the starting point of multiple different chains. It gets complicated at some point but I think other approaches result in code that is even harder to understand.