freeCodeCamp/curriculum/challenges/english/02-javascript-algorithms-and-data-structures/basic-javascript/manipulating-complex-objects.md

id, title, challengeType, videoUrl, forumTopicId, dashedName

id	title	challengeType	videoUrl	forumTopicId	dashedName
56533eb9ac21ba0edf2244cb	Manipulating Complex Objects	1	https://scrimba.com/c/c9yNMfR	18208	manipulating-complex-objects

--description--

Sometimes you may want to store data in a flexible Data Structure. A JavaScript object is one way to handle flexible data. They allow for arbitrary combinations of strings, numbers, booleans, arrays, functions, and objects.

Here's an example of a complex data structure:

const ourMusic = [
  {
    "artist": "Daft Punk",
    "title": "Homework",
    "release_year": 1997,
    "formats": [ 
      "CD", 
      "Cassette", 
      "LP"
    ],
    "gold": true
  }
];

This is an array which contains one object inside. The object has various pieces of metadata about an album. It also has a nested formats 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, "artist": "Daft Punk" is a property that has a key of artist and a value of Daft Punk. JavaScript Object Notation or JSON is a related data interchange format used to store data.

{
  "artist": "Daft Punk",
  "title": "Homework",
  "release_year": 1997,
  "formats": [ 
    "CD",
    "Cassette",
    "LP"
  ],
  "gold": true
}

Note: You will need to place a comma after every object in the array, unless it is the last object in the array.

--instructions--

Add a new album to the myMusic array. Add artist and title strings, release_year number, and a formats array of strings.

--hints--

myMusic should be an array

assert(Array.isArray(myMusic));

myMusic should have at least two elements

assert(myMusic.length > 1);

The elements in the myMusic array should be objects

myMusic.forEach(object => {assert.typeOf(object, 'object')})

Your object in myMusic should have at least 4 properties

myMusic.forEach(object => {assert(Object.keys(object).length > 3); });

Your object in myMusic should contain the property artist which is a string

myMusic.forEach(object => {
  assert.containsAllKeys(object, ['artist']);
  assert.typeOf(object.artist, 'string')
})

Your object in myMusic should contain the property title which is a string

myMusic.forEach(object => {
  assert.containsAllKeys(object, ['title']);
  assert.typeOf(object.title, 'string')
})

Your object in myMusic should contain the property release_year which is a number

myMusic.forEach(object => {
  assert.containsAllKeys(object, ['release_year']);
  assert.typeOf(object.release_year, 'number')
})

Your object in myMusic should contain a formats property which is an array

myMusic.forEach(object => {
  assert.containsAllKeys(object, ['formats']);
  assert.typeOf(object.formats, 'array')
})

formats should be an array of strings with at least two elements

myMusic.forEach(object => {
  object.formats.forEach(format => {
    assert.typeOf(format, 'string')
  });
  assert.isAtLeast(object.formats.length, 2)
})

--seed--

--after-user-code--

(function(x){ if (Array.isArray(x)) { return JSON.stringify(x); } return "myMusic is not an array"})(myMusic);

--seed-contents--

const myMusic = [
  {
    "artist": "Billy Joel",
    "title": "Piano Man",
    "release_year": 1973,
    "formats": [
      "CD",
      "8T",
      "LP"
    ],
    "gold": true
  }
];

--solutions--

const myMusic = [
  {
    "artist": "Billy Joel",
    "title": "Piano Man",
    "release_year": 1973,
    "formats": [
      "CS",
      "8T",
      "LP" ],
    "gold": true
  },
  {
    "artist": "ABBA",
    "title": "Ring Ring",
    "release_year": 1973,
    "formats": [
      "CS",
      "8T",
      "LP",
    "CD",
  ]
  }
];