Sometimes you may want to store data in a flexible <dfn>Data Structure</dfn>. A JavaScript object is one way to handle flexible data. They allow for arbitrary combinations of <dfn>strings</dfn>, <dfn>numbers</dfn>, <dfn>booleans</dfn>, <dfn>arrays</dfn>, <dfn>functions</dfn>, and <dfn>objects</dfn>.
This is an array which contains one object inside. The object has various pieces of <dfn>metadata</dfn> about an album. It also has a nested <code>"formats"</code> array. If you want to add more album records, you can do this by adding records to the top level array.
Objects hold data in a property, which has a key-value format. In the example above, <code>"artist": "Daft Punk"</code> is a property that has a key of <code>"artist"</code> and a value of <code>"Daft Punk"</code>.
<ahref='http://www.json.org/'target=_blank>JavaScript Object Notation</a> or <code>JSON</code> is a related data interchange format used to store data.
<strong>Note</strong><br>You will need to place a comma after every object in the array, unless it is the last object in the array.
</section>
## Instructions
<sectionid='instructions'>
Add a new album to the <code>myMusic</code> array. Add <code>artist</code> and <code>title</code> strings, <code>release_year</code> number, and a <code>formats</code> array of strings.
testString: assert(myMusic.length > 1, '<code>myMusic</code> should have at least two elements');
- text: <code>myMusic[1]</code> should be an object
testString: assert(typeof myMusic[1] === 'object', '<code>myMusic[1]</code> should be an object');
- text: <code>myMusic[1]</code> should have at least 4 properties
testString: assert(Object.keys(myMusic[1]).length > 3, '<code>myMusic[1]</code> should have at least 4 properties');
- text: <code>myMusic[1]</code> should contain an <code>artist</code> property which is a string
testString: assert(myMusic[1].hasOwnProperty('artist') && typeof myMusic[1].artist === 'string', '<code>myMusic[1]</code> should contain an <code>artist</code> property which is a string');
- text: <code>myMusic[1]</code> should contain a <code>title</code> property which is a string
testString: assert(myMusic[1].hasOwnProperty('title') && typeof myMusic[1].title === 'string', '<code>myMusic[1]</code> should contain a <code>title</code> property which is a string');
- text: <code>myMusic[1]</code> should contain a <code>release_year</code> property which is a number
testString: assert(myMusic[1].hasOwnProperty('release_year') && typeof myMusic[1].release_year === 'number', '<code>myMusic[1]</code> should contain a <code>release_year</code> property which is a number');
- text: <code>myMusic[1]</code> should contain a <code>formats</code> property which is an array
testString: assert(myMusic[1].hasOwnProperty('formats') && Array.isArray(myMusic[1].formats), '<code>myMusic[1]</code> should contain a <code>formats</code> property which is an array');
testString: assert(myMusic[1].formats.every(function(item) { return (typeof item === "string")}) && myMusic[1].formats.length > 1, '<code>formats</code> should be an array of strings with at least two elements');