Prototype pattern

Information drawn from

• Medium - Javascript design patterns

This pattern is an object-based creational design pattern. In this, we use a sort of a “skeleton” of an existing object to create or instantiate new objects.

This pattern is specifically important and beneficial to JavaScript because it utilizes prototypal inheritance instead of a classic object-oriented inheritance. Hence, it plays to JavaScript’s strength and has native support.

In this example, we have a car object that we use as the prototype to create another object myCar with JavaScript’s Object.create feature and define an extra property owner on the new object.

// using Object.create as was recommended by ES5 standard
const car = {
  noOfWheels: 4,
  start() {
    return 'started';
  },
  stop() {
    return 'stopped';
  },
};

// Object.create(proto[, propertiesObject])

const myCar = Object.create(car, { owner: { value: 'John' } });

console.log(myCar.__proto__ === car); // true

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Last update on 30 Jan 2020

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