如何为对象数组元素生成包含自身ID与父级ID的parents数组？

你的问题在于原代码只处理了直接父级，没法应对多级嵌套的场景（比如id=4的元素，需要追溯到父级的父级id=1）。下面是可行的实现方案：

核心思路 #

1. 先把数组转换成以id为键的映射对象，这样可以快速查找任意节点的父节点，避免反复遍历数组浪费性能。
2. 对每个节点，向上遍历所有父节点直到parentId为0，收集所有层级的ID（包括自身），组成parents数组。

代码实现 #

方式一：迭代遍历（推荐，避免递归深度问题）

const flattenArray = [
    {"id": "1","name": "Car","parentId": "0","parents": []},
    {"id": "2","name": "Car > Steering wheel","parentId": "1","parents": []},
    {"id": "3","name": "Car > Wheel","parentId": "1","parents": []},
    {"id": "4","name": "Car > Wheel > Wheel rim","parentId": "3","parents": []},
    {"id": "5","name": "Bus","parentId": "0","parents": []},
    {"id": "6","name": "Bus > Wheel","parentId": "5","parents": []}
];

// 创建节点映射表
const nodeMap = new Map();
flattenArray.forEach(node => nodeMap.set(node.id, node));

// 为每个节点生成parents数组
flattenArray.forEach(node => {
    const parents = [];
    let currentNode = node;
    
    // 向上遍历直到顶层节点（parentId为0）
    while (currentNode.parentId !== "0") {
        parents.unshift(currentNode.id); // 从父到子的顺序，所以插入数组头部
        currentNode = nodeMap.get(currentNode.parentId);
    }
    // 加入顶层节点的ID
    parents.unshift(currentNode.id);
    node.parents = parents;
});

console.log(JSON.stringify(flattenArray, null, 2));

方式二：递归实现（代码更简洁）

const flattenArray = [
    {"id": "1","name": "Car","parentId": "0","parents": []},
    {"id": "2","name": "Car > Steering wheel","parentId": "1","parents": []},
    {"id": "3","name": "Car > Wheel","parentId": "1","parents": []},
    {"id": "4","name": "Car > Wheel > Wheel rim","parentId": "3","parents": []},
    {"id": "5","name": "Bus","parentId": "0","parents": []},
    {"id": "6","name": "Bus > Wheel","parentId": "5","parents": []}
];

const nodeMap = new Map();
flattenArray.forEach(node => nodeMap.set(node.id, node));

// 递归获取当前节点的所有父级ID链
function getParentIds(node) {
    if (node.parentId === "0") {
        return [node.id];
    }
    const parentNode = nodeMap.get(node.parentId);
    return [...getParentIds(parentNode), node.id];
}

flattenArray.forEach(node => {
    node.parents = getParentIds(node);
});

console.log(JSON.stringify(flattenArray, null, 2));

代码说明 #

• 映射表nodeMap的作用是将节点ID和节点对象关联，让查找父节点的操作从O(n)降到O(1)，大幅提升效率。
• 迭代方式通过while循环向上遍历父节点，用unshift保证ID顺序是从顶层父节点到当前节点。
• 递归方式则通过函数调用自身，先获取父节点的ID链，再追加当前节点ID，逻辑更直观。

内容的提问来源于stack exchange，提问作者aries