Challenge: Visitor Pattern

Problem statement

In this challenge, you need to implement the visitor pattern to separate Rock music from the other genres of music by creating a separate playlist. You need to implement the RockMusicVisitor class for this purpose. As you can see, it contains the visit method, which should return the rock music playlist.

Note: the rock music playlist only needs to contain the names of the songs, not the entire Song object.

Next, you need to implement a Song class. A Song object will have the following properties: name and genre. You also need to define the two functions: getName and getGenre.

Finally, you need to implement the MusicLibrary class. It should store a list of all the songs, regardless of the genres. You need to implement the addSong function to add a song and accept function to allow the RockMusicVisitor to visit the music library.

Input

The accept function is called with RockMusicVisitor as a parameter

Output

A playlist containing names of all the rock songs from the library is returned

Sample input

var rockMusicVisitor = new RockMusicVisitor()
var song1 = new Song("Bohemian Rhapsody","Rock")
var song2 = new Song("Stairway to Heaven","Rock")
var song3 = new Song("Oops I did it again", "Pop")
var song4 = new Song("Crazy", "Country")
var musicLibrary = new MusicLibrary()
musicLibrary.addSong(song1)
musicLibrary.addSong(song2)
musicLibrary.addSong(song3)
musicLibrary.addSong(song4)
console.log(musicLibrary.accept(rockMusicVisitor))

Sample output

["Bohemian Rhapsody","Stairway to Heaven"]