freeCodeCamp/guide/english/certifications/javascript-algorithms-and-d.../object-oriented-programming/add-methods-after-inheritance/index.md

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2018-10-12 19:37:13 +00:00
---
title: Add Methods After Inheritance
---
## Add Methods After Inheritance
### Method
Just like the following example, a new instance of an object - `Dog` - must be created and the `prototype` must be set.
```javascript
function Bird() { }
Bird.prototype = Object.create(Animal.prototype);
Bird.prototype.constructor = Bird;
```
Then a new function - `bark()` - must be added to the Dog prototype.
### Solution
```javascript
function Animal() { }
Animal.prototype.eat = function() { console.log("nom nom nom"); };
function Dog() { }
// Add your code below this line
Dog.prototype = Object.create(Animal.prototype);
Dog.prototype.constructor = Dog;
Dog.prototype.bark = function() {
console.log("Woof woof!");
};
// Add your code above this line
let beagle = new Dog();
beagle.eat(); // Should print "nom nom nom"
beagle.bark(); // Should print "Woof!"
```