javascript - 如何循环遍历嵌套数组并为每个级别插入 id 和parentId？

Question

如何循环嵌套数组并为每个级别插入 id 和parentId？

这就是我所拥有的:

{
    "locations": [
        {
            "name": "Europe",
            "children": [
                {
                    "name": "Denmark",
                    "children": [
                        {
                            "name": "Copenhagen",
                            "population": [
                                {
                                    "people": "602481"
                                }
                            ]
                        }
                    ]
                },
                {
                    "name": "South Europe",
                    "children": [
                        {
                            "name": "Spain",
                            "children": [
                                {
                                    "name": "Madrid",
                                    "population": [
                                        {
                                            "people": "6550000"
                                        }
                                    ]
                                },
                                {
                                    "name": "Barcelona",
                                    "population": [
                                        {
                                            "people": "5515000"
                                        }
                                    ]
                                }
                            ]
                        }
                    ]
                }
            ]
        },
        {
            "name": "Asia",
            "children": [
                {
                    "name": "East Asia",
                    "children": [
                        {
                            "name": "China",
                            "children": [
                                {
                                    "name": "Beijing",
                                    "population": [
                                        {
                                            "people": "21540000"
                                        }
                                    ]
                                }
                            ]
                        }
                    ]
                }
            ]
        }
    ]
}

这就是我想要的:

{
    "locations": [
        {
            "id": "AP1",
            "name": "Europe",
            "children": [
                {
                    "id": "AP1.1",
                    "parentId": "AP1",
                    "name": "Denmark",
                    "children": [
                        {
                            "id": "AN1",
                            "parentId": "AP1.1",
                            "name": "Copenhagen",
                            "population": [
                                {
                                    "people": "602481"
                                }
                            ]
                        }
                    ]
                },
                {
                    "id": "AP1.2",
                    "parentId": "AP1",
                    "name": "South Europe",
                    "children": [
                        {
                            "id": "AP1.2.1",
                            "parentId": "AP1.2",
                            "name": "Spain",
                            "children": [
                                {
                                    "id": "AN2",
                                    "parentId": "AP1.2.1",
                                    "name": "Madrid",
                                    "population": [
                                        {
                                            "people": "6550000"
                                        }
                                    ]
                                },
                                {
                                    "id": "AN3",
                                    "parentId": "AP1.2.1",
                                    "name": "Barcelona",
                                    "population": [
                                        {
                                            "people": "5515000"
                                        }
                                    ]
                                }
                            ]
                        }
                    ]
                }
            ]
        },
        {
            "id": "AP2",
            "name": "Asia",
            "children": [
                {
                    "id": "AP2.1",
                    "parentId": "AP2",
                    "name": "East Asia",
                    "children": [
                        {
                            "id": "AP2.1.1",
                            "parentId": "AP2.1",
                            "name": "China",
                            "children": [
                                {
                                    "id": "AN4",
                                    "parentId": "AP2.1.1",
                                    "name": "Beijing",
                                    "population": [
                                        {
                                            "people": "21540000"
                                        }
                                    ]
                                }
                            ]
                        }
                    ]
                }
            ]
        }
    ]
}

我对 JavaScript 比较陌生，我只知道如何使用基本的 for 循环来循环第一个数组，即欧洲和亚洲。我实际上如何在层次结构中一直循环？

Answer 1

你可以这样做:

const obj = {
  "locations": [{
      "name": "Europe",
      "children": [{
          "name": "Denmark",
          "children": [{
            "name": "Copenhagen",
            "population": [{
              "people": "602481"
            }]
          }]
        },
        {
          "name": "South Europe",
          "children": [{
            "name": "Spain",
            "children": [{
                "name": "Madrid",
                "population": [{
                  "people": "6550000"
                }]
              },
              {
                "name": "Barcelona",
                "population": [{
                  "people": "5515000"
                }]
              }
            ]
          }]
        }
      ]
    },
    {
      "name": "Asia",
      "children": [{
        "name": "East Asia",
        "children": [{
          "name": "China",
          "children": [{
            "name": "Beijing",
            "population": [{
              "people": "21540000"
            }]
          }]
        }]
      }]
    }
  ]
}

function recur(arr, prevId = undefined) {
  let countId = 0;

  arr.forEach(item => {
    countId++;
    
    if (prevId) {
      item.id = prevId + '.' + countId;
      item.parentId = prevId;
    } else {
      item.id = countId.toString();
    }

    if ('children' in item && item.children.length > 0) {
      recur(item.children, item.id);
    }
  });
}

recur(obj.locations);
document.getElementById('output').innerHTML = JSON.stringify(obj, undefined, 4);

<pre id="output"></pre>

您需要递归的说法是不正确的。您也可以迭代地执行此操作，如果您想了解这一点，您可能想从这里开始:Tree Traversal on Wikipedia .

<小时/>

编辑:只是注意到应该有一个关于 ids 的命名方案，但由于您没有指定它是什么，我无法提供帮助。基本上，您需要使用条件来扩展此函数，以确定 id 中的实际字符串。