text: class treeNode {
    constructor(value) {
      this.value = value;
      this.descendants = [];
    }
  }
  
  // create nodes with values
  const root = new treeNode("pet store");
  const cat = new treeNode("cat");
  const dog = new treeNode("dog");
  
  // associate children with its parent
  root.descendants.push(dog, cat);
  
  const beagle = new treeNode("beagle");
  const golden = new treeNode("golden retriever");
  const husky = new treeNode("husky");
  
  dog.descendants.push(beagle, golden, husky);
  
  const shortHair = new treeNode("English short hair");
  const garfield = new treeNode("garfield");
  
  cat.descendants.push(shortHair, garfield);