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

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title: Add Methods After Inheritance
---
# Add Methods After Inheritance

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## Problem Explanation

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. 


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## Solutions

<details><summary>Solution 1 (Click to Show/Hide)</summary>

```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!"
```
</details>