js数组对象转树结构

原始数组对象：

let arr = [
    { id: 1, name: "节点1", parentId: 0 },
    { id: 2, name: "节点2", parentId: 1 },
    { id: 3, name: "节点3", parentId: 1 },
    { id: 4, name: "节点4", parentId: 2 },
    { id: 5, name: "节点5", parentId: 3 },
    { id: 6, name: "节点6", parentId: 5 },
    { id: 7, name: "节点7", parentId: 6 },
    { id: 8, name: "节点8", parentId: 6 }
];

1、非递归算法

function listToTree(data){
    let idObj={}
    data.forEach(item => {
        idObj[item.id]=item
    })
    let treeData=[]
    data.forEach(item=>{
        let parent=idObj[item.parentId]
        if(parent){
            parent.children=parent.children||[]
            parent.children.push(item)
        }else{
            treeData.push(item)
        }
    })
    return treeData
}

2、递归算法

function listToTreeLoop(data){
    function getNode(id){
        let arr=[]
        data.forEach((item)=>{
            if(item.parentId==id){
                item.children=getNode(item.id)
                arr.push(item)
            }
        })
        return arr
    }
    return getNode(0)
}

处理结果：