js实现无限级分类

let arr = [
 
    {id:1,name:"php",pid:0},
    {id:2,name:"php基础",pid:1},
    {id:3,name:"php面向对象",pid:1},
    {id:4,name:"python",pid:0},
    {id:5,name:"python迭带器",pid:4},
    {id:6,name:"python面向对象",pid:4},
    {id:7,name:"python网络编程",pid:4},
];
 
// 查询一级分类
function findChild(arr,id) {
    let childs = [];
    arr.forEach(v=>{
        if (v.pid == id){
            childs.push(v);
        }
    });
    return childs;
}
 
//
function build_tree(id) {
   let childs=  findChild(arr,id);
   if (childs.length==0){
       return null;
   }
 
   // 对于父节点为0的进行循环，然后查出父节点为上面结果id的节点内容
   childs.forEach((v,k)=>{
        let buildTree = build_tree(v.id);
        if (null != buildTree){
            v['children'] = buildTree;
        }
   });
 
    return childs;
 
}
 
console.log(build_tree(0));