javascript-polymerHow can I implement polymorphism in a JavaScript application?

Polymorphism in JavaScript can be implemented using the prototype object. Polymorphism allows the same interface to be used to access different objects. To illustrate this concept, consider the following example:

function Animal(name) {
  this.name = name;
}

Animal.prototype.speak = function() {
  console.log(`${this.name} says something`);
}

function Cat(name) {
  Animal.call(this, name);
}

Cat.prototype = Object.create(Animal.prototype);

Cat.prototype.speak = function() {
  console.log(`${this.name} meows`);
}

const animal = new Animal('Animal');
const cat = new Cat('Cat');

animal.speak(); // Animal says something
cat.speak(); // Cat meows

In the example, Animal and Cat are two different objects. However, both objects have a speak method which is defined in the prototype object. This allows the same interface to be used to access different objects.

Code explanation

1. function Animal(name) - This is the constructor function for the Animal object. It takes a name as an argument and sets it as a property of the object.
2. Animal.prototype.speak - This is a method of the Animal object which is defined in the prototype object. It logs a message to the console.
3. function Cat(name) - This is the constructor function for the Cat object. It takes a name as an argument and sets it as a property of the object.
4. Cat.prototype = Object.create(Animal.prototype) - This line sets the prototype of the Cat object to the prototype of the Animal object. This allows the same interface to be used for both objects.
5. Cat.prototype.speak - This is a method of the Cat object which is defined in the prototype object. It logs a message to the console.

Helpful links

• MDN - Object.create
• MDN - Prototypes

Edit this code on GitHub