--- id: 56bbb991ad1ed5201cd392d0 title: Build JavaScript Objects challengeType: 1 videoUrl: 'https://scrimba.com/c/cWGkbtd' --- ## Description <section id='description'> You may have heard the term <code>object</code> before. Objects are similar to <code>arrays</code>, except that instead of using indexes to access and modify their data, you access the data in objects through what are called <code>properties</code>. Objects are useful for storing data in a structured way, and can represent real world objects, like a cat. Here's a sample cat object: <blockquote>var cat = {<br> "name": "Whiskers",<br> "legs": 4,<br> "tails": 1,<br> "enemies": ["Water", "Dogs"]<br>};</blockquote> In this example, all the properties are stored as strings, such as - <code>"name"</code>, <code>"legs"</code>, and <code>"tails"</code>. However, you can also use numbers as properties. You can even omit the quotes for single-word string properties, as follows: <blockquote>var anotherObject = {<br> make: "Ford",<br> 5: "five",<br> "model": "focus"<br>};</blockquote> However, if your object has any non-string properties, JavaScript will automatically typecast them as strings. </section> ## Instructions <section id='instructions'> Make an object that represents a dog called <code>myDog</code> which contains the properties <code>"name"</code> (a string), <code>"legs"</code>, <code>"tails"</code> and <code>"friends"</code>. You can set these object properties to whatever values you want, as long <code>"name"</code> is a string, <code>"legs"</code> and <code>"tails"</code> are numbers, and <code>"friends"</code> is an array. </section> ## Tests <section id='tests'> ```yml tests: - text: <code>myDog</code> should contain the property <code>name</code> and it should be a <code>string</code>. testString: assert((function(z){if(z.hasOwnProperty("name") && z.name !== undefined && typeof z.name === "string"){return true;}else{return false;}})(myDog), '<code>myDog</code> should contain the property <code>name</code> and it should be a <code>string</code>.'); - text: <code>myDog</code> should contain the property <code>legs</code> and it should be a <code>number</code>. testString: assert((function(z){if(z.hasOwnProperty("legs") && z.legs !== undefined && typeof z.legs === "number"){return true;}else{return false;}})(myDog), '<code>myDog</code> should contain the property <code>legs</code> and it should be a <code>number</code>.'); - text: <code>myDog</code> should contain the property <code>tails</code> and it should be a <code>number</code>. testString: assert((function(z){if(z.hasOwnProperty("tails") && z.tails !== undefined && typeof z.tails === "number"){return true;}else{return false;}})(myDog), '<code>myDog</code> should contain the property <code>tails</code> and it should be a <code>number</code>.'); - text: <code>myDog</code> should contain the property <code>friends</code> and it should be an <code>array</code>. testString: assert((function(z){if(z.hasOwnProperty("friends") && z.friends !== undefined && Array.isArray(z.friends)){return true;}else{return false;}})(myDog), '<code>myDog</code> should contain the property <code>friends</code> and it should be an <code>array</code>.'); - text: <code>myDog</code> should only contain all the given properties. testString: assert((function(z){return Object.keys(z).length === 4;})(myDog), '<code>myDog</code> should only contain all the given properties.'); ``` </section> ## Challenge Seed <section id='challengeSeed'> <div id='js-seed'> ```js // Example var ourDog = { "name": "Camper", "legs": 4, "tails": 1, "friends": ["everything!"] }; // Only change code below this line. var myDog = { }; ``` </div> ### After Test <div id='js-teardown'> ```js (function(z){return z;})(myDog); ``` </div> </section> ## Solution <section id='solution'> ```js var myDog = { "name": "Camper", "legs": 4, "tails": 1, "friends": ["everything!"] }; ``` </section>