javascript将list转换成树状结构的实例

/**   * 将list装换成tree   * @param {Object} myId 数据主键id   * @param {Object} pId  数据关联的父级id   * @param {Object} list list集合   */  function listToTree(myId,pId,list){   function exists(list, parentId){    for(var i=0; i<list.length; i++){     if (list[i][myId] == parentId) return true;    }    return false;   }      var nodes = [];   // get the top level nodes   for(var i=0; i<list.length; i++){    var row = list[i];    if (!exists(list, row[pId])){     nodes.push(row);    }   }      var toDo = [];   for(var i=0; i<nodes.length; i++){    toDo.push(nodes[i]);   }   while(toDo.length){    var node = toDo.shift(); // the parent node    // get the children nodes    for(var i=0; i<list.length; i++){     var row = list[i];     if (row[pId] == node[myId]){      //var child = {id:row.id,text:row.name};      if (node.children){       node.children.push(row);      } else {       node.children = [row];      }      toDo.push(row);     }    }   }   return nodes;  }    var list=[   {"ids":1,"parendId":0,"name":"Foods",url:"wwww"},   {"ids":2,"parentId":1,"name":"Fruits"},   {"ids":3,"parentId":1,"name":"Vegetables"},   {"ids":4,"parentId":2,"name":"apple"},   {"ids":5,"parentId":2,"name":"orange"},   {"ids":6,"parentId":3,"name":"tomato"},   {"ids":7,"parentId":3,"name":"carrot"},   {"ids":8,"parentId":3,"name":"cabbage"},   {"ids":9,"parentId":3,"name":"potato"},   {"ids":10,"parentId":3,"name":"lettuce"},      {"ids":11,"parendId":0,"name":"Foods"},   {"ids":12,"parentId":11,"name":"Fruits"},   {"ids":13,"parentId":11,"name":"Vegetables"},   {"ids":14,"parentId":12,"name":"apple"},   {"ids":15,"parentId":12,"name":"orange"},   {"ids":16,"parentId":13,"name":"tomato"},   {"ids":17,"parentId":13,"name":"carrot"},   {"ids":18,"parentId":13,"name":"cabbage"},   {"ids":19,"parentId":13,"name":"potato"},   {"ids":20,"parentId":13,"name":"lettuce"}  ];    console.log(JSON.stringify(listToTree("ids","parentId",list)));  console.log(listToTree("ids","parentId",list));