2 Functional thinking in action

In this chapter

This chapter will give a broad overview of the two big ideas we will address in this book. Your main goal should be to get a taste of thinking with FP. Don’t worry about understanding everything right away. Remember that each of these ideas will be addressed in several chapters later on. This will be a whirlwind tour of functional thinking in action.

Welcome to Toni’s Pizza

Welcome to Toni’s Pizza. The year is 2118. It turns out people still like pizza in the future. But all of the pizza is made by robots. And the robots are programmed in JavaScript. Go figure.

Toni has applied a lot of functional thinking to the code that runs her restaurants. We’re going to take a brief tour through some of her systems, including the kitchen and her inventory, and see how she has applied the two levels of functional thinking.

Just so you don’t have to flip back, here are the two levels again. Here’s how Toni uses them.

Part 1: Distinguishing actions, calculations, and data

Part 2: Using first-class abstractions

Part 1: Distinguishing actions, calculations, and data

1. Actions

2. Calculations

3. Data

Organizing code by “rate of change”

A first glimpse of stratified design

Part 2: First-class abstractions

As applied to a robotic kitchen

Timelines visualize distributed systems

Multiple timelines can execute in different orderings

Hard-won lessons about distributed systems

Toni does a postmortem

Cutting the timeline: Making the robots wait for each other

Positive lessons learned about timelines

Retrospective on coordinating robots

Conclusion

Summary

Up next…