OOP with Functions in JavaScript

The JavaScript community is constantly a hotbed for heated discussions over best paradigms, hippest frameworks, and coolest opinions. Honestly, I think it’s great, to have some an open and enthusiastic community. You have people coming in at all experience levels finding a place where they can immediately participate and more importantly contribute. But the number of times these discussions devolve into argument of semantics is far more often than I’d like.

I want to deconstruct OOP from the perspective of using Function primitives. This isn’t strictly Functional programming. I just want to illustrate that value of OOP can be achieved piece-wise without subscribing to language specific constructs like Classes, which in the case of JavaScript are actually insufficient to fulfill the primary needs. I’ve heard this referred to as Factory Oriented programming. But really it’s just another perspective on a classic problem. And perhaps a better understanding of JavaScript comes with this journey.

So what is OOP?

Go do a google search. Wikipedia will tell you:

Object-oriented programming (OOP) is a programming paradigm based on the concept of “objects”, which can contain data, in the form of fields (often known as attributes), and code, in the form of procedures (often known as methods).

Alright. It’s programming using objects. That sounds easy. So this is OOP?

const pet = {
  type: 'dog',
  name: 'Jake',
  makeSound() {
    alert('Woof woof.');
  }
}

Well sort of… That is an object that happens to identify with being a dog but it’s sort of inconvenient if we want to have more than one dog. So lets make a factory function.

function createDog(name) {
  return {
    type: 'dog',
    name,
    makeSound() {
      alert('Woof woof.');
    }
  }
}
const pet = createDog('Jake');
const pet2 = createDog('Jackie');

Success. We now are using a factory function to create our objects. Our dogs have names, and they can bark.

As it turns out there is more to OOP than this. There is a reason that describing OOP is not a one liner. It’s the combination of several programming best practices in cohesive system. Most notably…