Functional Programming

The building block of functional programming is a function

A function is an abstraction that receives an input and produces an output

f(x) ⇒ y

A pure function is a function that returns the same return for the same input.

Pure functions are easy to test as you don’t have to mock external parts and there is no side effects.

You can functional programs composing functions.

Types define which values are valid for a given variables or function argument or return.

We can only compose functions that one