freeCodeCamp/curriculum/challenges/en/02-javascript-algorithms-and-data-structures/object-oriented-programming/create-a-method-on-an-object.en.md

---
id: 587d7dad367417b2b2512b75
title: Create a Method on an Object
challengeType: 1
---

## Description
<section id='description'>
<code>Objects</code> can have a special type of <code>property</code>, called a <code>method</code>.
<code>Methods</code> are <code>properties</code> that are functions. This adds different behavior to an <code>object</code>. Here is the <code>duck</code> example with a method:
<blockquote>let duck = {<br>&nbsp;&nbsp;name: "Aflac",<br>&nbsp;&nbsp;numLegs: 2,<br>&nbsp;&nbsp;sayName: function() {return "The name of this duck is " + duck.name + ".";}<br>};<br>duck.sayName();<br>// Returns "The name of this duck is Aflac."</blockquote>
The example adds the <code>sayName</code> <code>method</code>, which is a function that returns a sentence giving the name of the <code>duck</code>.
Notice that the <code>method</code> accessed the <code>name</code> property in the return statement using <code>duck.name</code>. The next challenge will cover another way to do this.
</section>

## Instructions
<section id='instructions'>
Using the <code>dog</code> <code>object</code>, give it a method called <code>sayLegs</code>. The method should return the sentence "This dog has 4 legs."
</section>

## Tests
<section id='tests'>

```yml
- text: <code>dog.sayLegs()</code> should be a function.
  testString: 'assert(typeof(dog.sayLegs) === ''function'', ''<code>dog.sayLegs()</code> should be a function.'');'
- text: <code>dog.sayLegs()</code> should return the given string - note that punctuation and spacing matter.
  testString: 'assert(dog.sayLegs() === ''This dog has 4 legs.'', ''<code>dog.sayLegs()</code> should return the given string - note that punctuation and spacing matter.'');'

```

</section>

## Challenge Seed
<section id='challengeSeed'>

<div id='js-seed'>

```js
let dog = {
  name: "Spot",
  numLegs: 4,
  
};

dog.sayLegs();
```

</div>



</section>

## Solution
<section id='solution'>


```js
let dog = {
  name: "Spot",
  numLegs: 4,
  sayLegs () {
    return 'This dog has ' + this.numLegs + ' legs.';
  }
};

dog.sayLegs();
```

</section>