Ios Swift扩展与其他类

我在做一个游戏，有一堆向量，每个向量对应于另一个向量中的一个SKSpriteNode。您能否扩展SKSpriteNode类以将我存储在其他向量中的属性包含在相应索引中，然后在SKScene的类声明/实现中创建ExtendedSKSpriteNode类型的对象？我试过了，但收效甚微

//Current Implementation
class OldScene: SKScene {
    var node1 = SKSpriteNode(imageNamed: "who cares")
    var node2 = SKSpriteNode(imageNamed: "doesn't matter")
    var node3 = SKSpriteNode(imageNamed: "this is instantiated")
    var nodeVector: [SKSpriteNode] = [node1, node2, node3]
    var timesWhenSomethingHappensToEachNode: [CGFloat] = [CGFloat(1.2), CGFloat(1.7), CGFloat(3.1)]
    var framesUntilThisOccurs: [Int] = [2, 30, 15]
}

//Desired implementation
extension SKSpriteNode {
    //timesWhenSomethingHappensToEachNode and framesUntilThisOccurs are made properties
    //of SKSpriteNode
    //probably happens in here
}

class NewScene: SKScene {
    //Can we instantiate those extended types here?
    var newNode1 = SKSpriteNode(imageNamed: "who cares")
    var newNode3 = SKSpriteNode(imageNamed: "this is instantiated")

    var nodeOneTime = newNode1.timesWhenSomethingHappensToEachNode
    var framesUntilThreeHappens = newNode3.framesUntilThisOccurs
}

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既然可以创建一个SKSpriteNode子类，为什么还要扩展SKSpriteNode？一个扩展不能有存储的属性，但这里有一个很好的观点，paul。多态性和条件向下转换应该使这变得非常简单。谢谢