Composing Software

Pure Functions

Pure functions are essential for a variety of purposes, including functional programming, concurrency, and reliable UX components. But what does “pure function” mean?

Before we can tackle what a pure function is, it’s probably a good idea to take a closer look at functions. There may be a different way to look at them that will make functional programming easier to understand.

What is a Function?

A function is a process which takes some input, called arguments, and produces some output called a return value. Functions may serve the following purposes:

• Mapping: Produce some output based on given inputs. A function maps input values to output values.
• Procedures: A function may be called to perform a sequence of steps. The sequence ...