javascript计算深度嵌套数组元素的个数

Question

我得到了以下数组:

let data =  [
        {"title": {number: 1},
            "children": [
                {"title": {number: 1.1}},
                {"title": {number: 1.2}},
                {"title": {number: 1.3}},
                {"title": {number: 1.4}},
                {"title": {number: 1.5}}
            ]
        },
        {"title": {number: 2},
            "children": [
                {"title":{number: 2.1}},
                {"title":{number: 2.2},
                    "children": [
                        {"title":{number: 2.2.1}},
                        {"title":{number: 2.2.2}},
                        {"title":{number: 2.2.3}},
                        {"title":{number: 2.2.4}} 
                    ]
                },
                {"title":{number: 2.3}},
                {"title":{number: 2.4}}
            ]
        },
        {"title": {number: 3},
            "children": []
        }
    ];

该数组中的每个元素都可以更改其位置，可以添加新元素，也可以删除现有元素。任务是重新计算元素编号以保持其正确的顺序。例如，如果删除编号为 2.2.2 的元素，则其他元素将变为 2.2.1、2.2.2 和 2.2 .3。如果某个元素及其子元素被删除，则所有其他元素的数字也应该重新计算。任何如何做到这一点的想法都将受到欢迎。谢谢

Answer 1

您可以创建递归函数，每次对象结构发生变化时都会调用该函数，以重新计算树中每个元素的位置。

function recalc(data, prev = '') {
  data.forEach((e, i) => {
    let dot = prev ? '.' : '';
    let number = prev + dot + (i + 1);

    if (e.children) {
      recalc(e.children, number)
    }

    if (e.title) {
      e.title.number = number
    }
  })
}

const data1 = [{"title":{"number":1},"children":[{"title":{"number":1.1}},{"title":{"number":1.2}},{"title":{"number":1.3}},{"title":{"number":1.4}},{"title":{"number":1.5}}]},{"title":{"number":2},"children":[{"title":{"number":2.1}},{"title":{"number":2.2},"children":[{"title":{"number":"2.2.1"}},{"title":{"number":"2.2.2"}},{"title":{"number":"2.2.3"}},{"title":{"number":"2.2.4"}}]},{"title":{"number":2.3}},{"title":{"number":2.4}}]},{"title":{"number":3},"children":[]}]
recalc(data1);
console.log(data1)

const data2 = [{"title":{"number":1},"children":[{"title":{"number":1.1}},{"title":{"number":1.2}},{"title":{"number":1.5}}]},{"title":{"number":2},"children":[{"title":{"number":2.1}},{"title":{"number":2.2},"children":[{"title":{"number":"2.2.3"}},{"title":{"number":"2.2.4"}}]},{"title":{"number":2.3}},{"title":{"number":2.4}}]},{"title":{"number":3},"children":[{title: {}, children: [{title: {}}, {title: {}}]}]}]
recalc(data2);
console.log(data2)