如何获得具有预定义值的顶级父级的所需类别树

Question

您好，我想从类别列表中获取子树。

这是我的输入数据

[
  { "parent_id": -1, "name": "Toothpaste", "id": 99 },
   {
        "parent_id": -1,
        "name": "Cake",
        "id": 3
    },
    {
        "parent_id": 3,
        "name": "Chocolate  Cake",
        "id": 4
    },
    {
        "parent_id": 3,
        "name": "Walnut Cake",
        "id": 5
    },
    {
        "parent_id": 4,
        "name": "Chocolate Cake mixin 1",
        "id": 6
    }
]

我想要的输出如下图所示

[ { "parent_id": -1, "name": "Toothpaste", "id": 99 },
   {
    "parent_id": -1,
    "name": "Cake",
    "id": 3,
    "children":[
        {
            "parent_id": 3,
            "name": "Chocolate  Cake",
            "id": 4,
            "children":[     //<--- observe this one not there in my output 
                {
                    "parent_id": 4,
                    "name": "Chocolate Cake mixin 1",
                    "id": 6
                }
            ]
        },
        {
            "parent_id": 3,
            "name": "Walnut Cake",
            "id": 5
        }
    ],
  }

]

我面临的问题是我无法将数据推送到第二级，即巧克力蛋糕正在生孩子，但我无法将其推送到巧克力蛋糕儿童中 p>

注意：解决方案必须适用于任何级别的嵌套

这是我尝试过的

function getChildrenTree(childList){
        let childMap = {};
        for(let i = 0; i < childList.length; i++){
           if(childList[i].parent_id === -1)
              childMap[childList[i].id] = {name:childList[i].name,children:[]};
          
        }
    
        for(let i = 0; i < childList.length; i++){
            if(childMap && childMap.hasOwnProperty(childList[i].parent_id) && childMap[childList[i].parent_id].hasOwnProperty('children')) childMap[childList[i].parent_id].children.push(childList[i]);
        }
         
       return Object.values(childMap);
    }

getChildrenTree([ { "parent_id": -1, "name": "Toothpaste", "id": 99 },{ "parent_id": -1, "name": "Cake", "id": 3 }, { "parent_id": 3, "name": "Chocolate  Cake", "id": 4 }, { "parent_id": 3, "name": "Walnut Cake", "id": 5 }, { "parent_id": 4, "name": "Chocolate Cake mixin 1", "id": 6 } ])

Answer 1

您可以尝试以下方法。

const flat = [
  { "parent_id": -1, "name": "Toothpaste", "id": 99 },
   {
        "parent_id": -1,
        "name": "Cake",
        "id": 3
    },
    {
        "parent_id": 3,
        "name": "Chocolate  Cake",
        "id": 4
    },
    {
        "parent_id": 3,
        "name": "Walnut Cake",
        "id": 5
    },
    {
        "parent_id": 4,
        "name": "Chocolate Cake mixin 1",
        "id": 6
    }
];

const makeTree = (arr, parent) => {
  const branch = arr.filter(node => node.parent_id === parent);
  branch.forEach(node => {
    const children = makeTree(arr, node.id);
    if (children.length) {
      node.children = children;
    }
  });
  return branch;
};

const tree = makeTree(flat, -1);

console.log(tree);

Answer 2

您可以使用单个循环和对象来收集节点并通过从根节点获取所有子节点来返回一棵树。

const
    buildTree = (data, root) => {
        var t = {};
        data.forEach(o => {
            Object.assign(t[o.id] = t[o.id] || {}, o);
            ((t[o.parent_id] ??= {}).children ??= []).push(t[o.id]);
        });
        return t[root].children
    },
    data = [{ parent_id: -1, name: "Toothpaste", id: 99 }, { parent_id: -1, name: "Cake", id: 3 }, { parent_id: 3, name: "Chocolate  Cake", id: 4 }, { parent_id: 3, name: "Walnut Cake", id: 5 }, { parent_id: 4, name: "Chocolate Cake mixin 1", id: 6 }],
    tree = buildTree(data, -1);


console.log(tree);

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