如何将可选链接与 nil 合并运算符一起使用？

Question

Using the enums and structures, implement the getArtistGenre() function. Given a Song as input, return the raw value of the artist's primary genre. If either the artist is nil or the primaryGenre is nil, then return an empty string. You must use optional chaining and the nil coalescing operator (??).

enum Genre: String {
    case country, blues, folk
}

struct Artist {
    let name: String
    var primaryGenre: Genre?
}

struct Song {
    let title: String
    let released: Int
    var artist: Artist?
}

func getArtistGenre(song: Song) -> String {
    
}

Answer 1

As the comments suggest:

func getArtistGenre(song: Song) -> String {
      return song.artist?.primaryGenre?.rawValue ?? “”
}