如何在Javascript中从数组创建树(父子对象) [英] How to create a tree (parent-child) object from Array in Javascript

问题描述

我有一个像这样的数组

[
  "parent1|child1|subChild1",
  "parent1|child1|subChild2",
  "parent|child2|subChild1",
  "parent1|child2|subChild2",
  "parent2|child1|subChild1",
  "parent2|child1|subChild2",
  "parent2|child2|subChild1",
.
.
.    
]

其中，我在|之前的第一个字符串是父级，而在| c之前的第二个字符串是是子项，第二个|之后的第三个字符串是子子项

Wherein my first string before | is the parent and the second string before | is the child and the third string after the second | is the subchild

如何将该数组转换为类似对象

How can I convert this array into an object like

[
 {
  "id": "parent1",
  "children":[
   {
    "id": "child1",
    "children":[
     {
      "id": "subChild1"
     }
    ]
   }
  ]
 }
]

父->子->子子对象

基于塞巴斯蒂安的回答，我在下面使用打字稿尝试了

Based on Sebastian's answer I tried below using typescript

private genTree(row) {
        let self = this;
        if (!row) {
            return;
        }
        const [parent, ...children] = row.split('|');
        if (!children || children.length === 0) {
            return [{
                id: parent,
                children: []
            }];
        }
        return [{
            id: parent,
            children: self.genTree(children.join('|'))
        }];
    }

    private mergeDeep(children) {
        let self = this;
        const res = children.reduce((result, curr) => {
            const entry = curr;
            const existing = result.find((e) => e.id === entry.id);
            if (existing) {
                existing.children = [].concat(existing.children, entry.children);
            } else {
                result.push(entry);
            }
            return result;
        }, []);
        for (let i = 0; i < res.length; i++) {
            const entry = res[i];
            if (entry.children && entry.children.length > 0) {
                entry.children = self.mergeDeep(entry.children);
            }
        };
        return res;
    }

private constructTree(statKeyNames){
    let self = this;
    const res = this.mergeDeep(statKeyNames.map(self.genTree).map(([e]) => e));
    console.log(res);
}

但这给了我

无法读取未定义的属性'genTree'"

Cannot read property 'genTree' of undefined" error

更新:

根据塞巴斯蒂安的评论，self.genTree更改为this.genTree.bind(this)，并且没有任何问题

As per Sebastian's comment changed self.genTree to this.genTree.bind(this) and it worked without any issues

推荐答案

您必须为此使用递归.在这里看看:

You have to use recursion for that. Take a look here:

const arr = [
  "parent1|child1|subChild1",
  "parent1|child1|subChild2",
  "parent|child2|subChild1",
  "parent1|child2|subChild2",
  "parent2|child1|subChild1",
  "parent2|child1|subChild2",
  "parent2|child2|subChild1"
];

function genTree(row) {

  const [parent, ...children] = row.split('|');

  if (!children || children.length === 0) {
    return [{
      id: parent,
      children: []
    }];
  }

  return [{
    id: parent,
    children: genTree(children.join('|'))
  }];
};

function mergeDeep(children) {

  const res = children.reduce((result, curr) => {

    const entry = curr;

    const existing = result.find((e) => e.id === entry.id);
    if (existing) {

      existing.children = [].concat(existing.children, entry.children);
    } else {
      result.push(entry);
    }

    return result;
  }, []);

  for (let i = 0; i < res.length; i++) {

    const entry = res[i];
    if (entry.children && entry.children.length > 0) {
      entry.children = mergeDeep(entry.children);
    }
  };

  return res;
}

const res = mergeDeep(arr.map(genTree).map(([e]) => e));
console.log(JSON.stringify(res, false, 2));

我在这里使用了两个帮助器:genTree(row)递归地从每一行生成一个简单的树，以及mergeDeep(children)减少arr.map(genTree).map(([e]) => e)结果中的第一级树，然后遍历数组并递归地执行每个条目的所有children都具有相同的含义.

I used two helpers here: genTree(row) which recursively generates a simple tree from each row, and mergeDeep(children) which reduces the first-level trees in the result of arr.map(genTree).map(([e]) => e), and then iterates over the array and recursively does the same thing to all children of each entry.

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