One of the most famous programming paradigms is object-oriented programming. Every developer, at some point, may have heard of this pattern and used it. The problem is, we have been using object oriented programming to some extent in our applications for a long time and sometimes that paradigm may not be the best approach to solve it. a specific problem.
Functional programming is a programming paradigm that has become popular and used by developers over the past few years. Some programming languages are specifically designed to work with this paradigm, such as Clojure, Elixir, Haskell, etc. We have a few different libraries in the JavaScript ecosystem that help us work with a more functional programming style in our applications, such as Ramda and Lodash. Sometimes we don’t need these libraries and we can work with just the core concepts of JavaScript to get more functional programming code.
Learning exactly how the functional programming paradigm works can make a world of difference in a developer’s career. The way a developer thinks, writes code, solves problems, all of these can be influenced by a programming model.
We need to know some functional programming concepts to implement this pattern in JavaScript applications. So let’s learn more about them.
What is Functional Programming?
compound and pure functions.
JavaScript is a multi-paradigm language, which means we can easily combine many different paradigms in a single piece of JavaScript code. We can use object-oriented, procedural and functional programming models simultaneously in JavaScript. The fact that JavaScript is multi-paradigm and allows us to work with many different programming methods is what makes this language so beautiful and powerful.
Functional programming has a few important concepts that we need to know and understand. By implementing these concepts in your applications, you will have more functional code. It will make a big difference to your application, making it easier to read, easier to use, easier to manage, easier to test, and error-free.
Let’s cover important functional programming concepts and how we can apply them in JavaScript. first class object
Functions in JavaScript are first-class objects, also known as “first-class citizens”. This means we can work with functions in JavaScript the same way we work with variables.
const sum = (a, b) => a + b; const resultSum = sum(1, 2); const sumAgain = (a, b, sum) => sum(a, b);
JavaScript
Functions in JavaScript are objects – they can have properties and bind to their constructor.
We can work with functions in JavaScript in many different ways. Eg:
- We can assign them in a variable as a value.
- We can pass them as arguments to other functions. We can return them as return value of another function.
- We can put them in different data structures.
The way JavaScript handles functions is what allows us to implement the functional programming model in JavaScript.
Pure Function
One of the most important concepts in the functional programming paradigm is pure function. Functional programming requires us to write pure, deterministic functions, and that’s what makes functional programming so beautiful and useful:
it forces us to write better code with pure functions, making our code easier to test and maintain. Pure functions are functions that, given a particular input, will always return the same output. Pure functions are designed to cause no side effects, e.g. writing to the console, modifying an object, reassigning a variable, etc.
const myName = (name) => 'Hello ${name}';myName("Leonardo") // Should always return "Hello Leonardo"
