Converts an array of items with ids and parent ids to a nested tree in a performant way

dataTree.go

type TreeNode struct {
	Id   string
	Name string
	Pid  string
	Sub  []*TreeNode
}

func CreateDataTree(data []TreeNode, maxDepth int) []*TreeNode {
	var hash = map[string]*TreeNode{}
	for i := range data {
		// 注意使用`for i, v := range`形式时，迭代变量v的地址始终指向同一个
		hash[data[i].Id] = &data[i]
	}

	var (
		ok   bool
		node *TreeNode
	)

	var dataTree = make([]*TreeNode, 0, maxDepth)
	for i := range data {
		if node, ok = hash[data[i].Pid]; ok {
			if len(node.Sub) == 0 {
				node.Sub = make([]*TreeNode, 0, maxDepth)
			}
			node.Sub = append(node.Sub, hash[data[i].Id])
		} else {
			dataTree = append(dataTree, hash[data[i].Id])
		}
	}
	return dataTree
}

data := []TreeNode{
	{
		Id:   "/1/",
		Pid:  "/",
		Name: "上衣",
	},
	{
		Id:   "/2/",
		Pid:  "/",
		Name: "裤子",
	},
	{
		Id:   "/1/3/",
		Pid:  "/1/",
		Name: "夹克",
	},
	{
		Id:   "/1/4/",
		Pid:  "/1/",
		Name: "西装",
	},
	{
		Id:   "/2/5/",
		Pid:  "/2/",
		Name: "运动裤",
	},
	{
		Id:   "/2/6/",
		Pid:  "/2/",
		Name: "牛仔裤",
	},
	{
		Id:   "/1/4/7/",
		Pid:  "/1/4/",
		Name: "中式西装",
	},
}

dataTree := CreateDataTree(data, 10)

// fmt.Println(dataTree[0].Sub[0].Name)
// fmt.Println(dataTree[0].Sub[1].Sub[0].Name)

fmt.Printf("%+v\n", dataTree)