问数组的嵌套类，希望获取外部数组的索引。

EN

//Node class
class Node {
    constructor(x, y, r, color, highlight, highlightColor) {
        this.x = x;
        this.y = y;
        this.r = r || 20;
        this.color = color || "#ff0";
        this.highlight = highlight || false;
        this.highlightColor = highlightColor || "#0000FF";
    }

  /* === PROPERTY: parentCreature === */
  get parentCreature() {
    return this._parentCreature;
  }
  set parentCreature(creature) {
    this._parentCreature = creature;
  }
  
  
  /* === METHODS: removeFromCreature === */
  removeFromCreature() {
    this._parentCreature = null;
  }

}

function setParentForNodes() {
  this.nodesArray.forEach(node => {
    node.parentCreature = this;
  });
}

// Creature class
class Creature {
    /* === CONSTRUCTOR === */
    constructor(nodes, muscles, nodeColors) {
        this.nodes = nodes;
        this.muscles = muscles;
        this.nodeColors = nodeColors || "#ff0";
        
        setParentForNodes.call(this);
    }


    /* === PROPERTY: nodesArray === */
    get nodesArray() {
      return this.nodes;
    }
    set nodesArray(value) {
      this.nodes = value;
      setParentForNodes.call(this);
    }
    
    /* === PROPERTY: musclesArray === */
    get musclesArray() {
      return this.musclesArray;
    }
    set musclesArray(value) {
      this.musclesArray = value;
    }
    
    
    /* === METHODS: removeNodes === */
    removeNodes() {
      this.nodes.forEach(node => {
        node.parentCreature = null;
      });
      this.nodes = null;
    }
}



class Creatures {
  /* === CONSTRUCTOR === */
  constructor(creaturesArray = []) {
    this.creatures = new Map();
    
    creaturesArray.forEach(creature => {
      this.creatures.set(creature.id, creature.model);
    });
  }
  
  /* === METHOD: addCreature === */
  addCreature(id, model) {
    if (this.creatures.has(id)) {
      console.log('Creature ID already exists');
      return;
    }
    
    this.creatures.set(id, model);
  }

  /* === METHOD: getCreatureById === */
  getCreatureById(id) {
    if (this.creatures.has(id)) {
      return this.creatures.get(id);
    }
    
    return null;
  }
}

// Create the nodes
var nodes = [
    new Node(100, 100),
    new Node(200, 200)
];

// Create the Goblin with the nodes.
var creatures = new Creatures([
    {
      id: 'goblin',
      model: new Creature(nodes, 'muscles')
    }
]);


// Create the dwarf, it has no nodes
creatures.addCreature('dwarf', new Creature([], 'muscles'));


const
  // Get the parent creature for the first node.
  parentCreatureForNode = nodes[0].parentCreature,
  // Get the creature instance for the dwarf.
  dwarf = creatures.getCreatureById('dwarf');
  
// Remove the nodes from the parent of the first node.
parentCreatureForNode.removeNodes();
// Assign the nodes to the dwarf.
dwarf.nodesArray = nodes;

// The goblin should report it has no nodes.
console.log(creatures.getCreatureById('goblin'));
// The dwarf should log it has 2 nodes.
console.log(creatures.getCreatureById('dwarf'));
// Make sure the node reports its parent is the dwarf.
console.log(nodes[0].parentCreature === dwarf);