Functional JavaScript

Chapter 9. Programming Without Class

When people are first exposed to JavaScript and its minimal set of tools (functions, objects, prototypes, and arrays), many are underwhelmed. Therefore, in order to “modify” JavaScript to conform to their idea of what it takes to model software solutions, they very often seek out or re-create class-based systems using the primordial ooze. This desire is completely understandable given that in general people will often seek the familiar. However, since you’ve come this far in exploring functional programming in JavaScript, it’s worth tying all of the threads from the previous chapters into a coherent exploration of how to reify functional and object-oriented thinking.

This chapter starts by walking the path of data and function thinking that I’ve talked about throughout the book. However, while thinking in functions and simple data is important, there will come a time when you may need to build custom abstractions. Therefore, I will cover a way to “mix” discrete behaviors together to compose more complex behaviors. I will also discuss how a functional API can be used to hide such customizations.

Data Orientation

Throughout the course of this book, I’ve intentionally defined my data modeling needs in terms of JavaScript primitives, arrays, and objects. That is, I’ve avoided creating a hierarchy of types in favor of composing simple data together to form higher-level concepts like tables (Chapter 8) and commands (Chapter 4). Adhering to a focus on ...