PlaylistItem.swift

import UIKit

class PlaylistItem {
    var track: iTrack?
    var next: PlaylistItem?
    weak var previous: PlaylistItem?
}

extension PlaylistItem: Equatable {
    static func ==(lhs: PlaylistItem, rhs: PlaylistItem) -> Bool {
        return lhs.track!.previewUrl! == rhs.track!.previewUrl!
    }
}