ES6 Classes

Before ES6, JavaScript used functions and the Prototype property to share methods across instances, which is known as Pseudoclassical Instantiation (new keyword). This approach required understanding the nuances of JavaScript’s prototype chain and constructor functions. Here’s an example of a pseudoclassical constructor:

function Animal(name, energy) {
  this.name = name
  this.energy = energy
}
 
Animal.prototype.eat = function(amount) {
  console.log(`${this.name} is eating.`)
  this.energy += amount
}
 
const leo = new Animal('Leo', 7)

The class keyword introduced in ES6 is syntactical sugar over the Pseudoclassical pattern. It offers a cleaner and more intuitive way to define a class’s constructor and its prototype methods. It aligns with the class-based inheritance found in other languages, making JavaScript more accessible to a broader range of developers and improving code readability and maintainability.

class Animal {
  constructor(name, energy) {
    this.name = name
    this.energy = energy
  }
  
  eat(amount) {
    console.log(`${this.name} is eating.`)
    this.energy += amount
  }
}
 
const leo = new Animal('Leo', 7)

The introduction of the class syntax is part of JavaScript’s evolution to improve developer experience without changing the fundamental prototype-based nature of the language.

References

• A Beginner’s Guide to JavaScript’s Prototype