问给定一个表示层次结构的数组，将数据输出到JS中的树形式

EN

function Node(word)
{
  this.value = word;
  this.children = {};
}

function AddDotChain(chain)
{
  let arr = chain.split('.');
  let currentNode = this;

  function recurse(currentIndex)
  {
    if(currentIndex === arr.length)
    {
      return;
    }

    let currentWord = arr[currentIndex];
    if(currentNode.children[currentWord])
    {
      currentNode = currentNode[currentWord];
      return recurse(currentIndex + 1);
    }

    let child = new Node(currentWord);
    currentNode.children[currentWord] = child;
    currentNode = child;
    return recurse(currentIndex + 1);
  }
}

var arr = ["transportation.cars.Mazda",
 "transportation.cars.Honda",
 "transportation.cars.Toyota",
 "transportation.train.lightRail",
 "transportation.train.rapidTransit",
 "transportation.waterVehicle.ferry",
 "transportation.waterVehicle.boats" 
 ];

function Node(data) {
	this.data = data;
	this.children = [];
}

function Tree(data) {
	this.root = null;
}

Tree.prototype.contains = function(data) {
	return this.find(data) ? true : false;
}

Tree.prototype.add = function(data, node) {
	const newNode = new Node(data);

	if (!this.root)	{
		this.root = newNode;
		return;
	}

	const parent = node ? this.find(node) : null;
	
	if (parent) {
		if (!this.contains(data)) {
				parent.children.push(newNode);
		}
	}
}

Tree.prototype.find = function(data) {
	if (this.root) {
		const queue = [this.root];
		while(queue.length) {
			const node = queue.shift();
			if (node && node.data === data) {
				return node;
			}

			for(var i = 0; i < node.children.length; i++) {
				const child = node.children[i];
				queue.push(child);
			}
		}
	}
	return null;
}

function createTreeOfTransportation(arr) {
	const tree = new Tree();
	for(var i = 0; i < arr.length; i++) {
		const element = arr[i];
		const nodes = element.split('.');

		for (var j = 0; j < nodes.length; j++) {
			const currentNode = nodes[j];
			const parent = nodes[j-1];
			console.log(j, parent);
			tree.add(currentNode, parent);
		}
	}
	
	return tree;
}

console.log(createTreeOfTransportation(arr));