将嵌套JSON展平为无索引的唯一对象数组

针对需要将嵌套JSON展平为数组形式（每个数组元素对应底层数组的单个值，并保留所有上层非数组字段）的需求，以下是实现方案：

核心思路 #

递归遍历JSON结构，遇到数组时对每个元素单独展开，将展开后的字段与上层已收集的字段进行笛卡尔积合并，最终生成每个底层值对应的完整对象数组。

实现代码 #

function flattenToArray(obj, parentKey = '', currentObj = {}) {
  let result = [];

  for (const key in obj) {
    if (!obj.hasOwnProperty(key)) continue;
    
    const value = obj[key];
    const newKey = parentKey ? `${parentKey}.${key}` : key;

    if (Array.isArray(value)) {
      // 遍历数组元素，递归处理后合并结果
      for (const item of value) {
        result = result.concat(flattenToArray(item, newKey, {...currentObj}));
      }
    } else if (typeof value === 'object' && value !== null) {
      // 递归处理嵌套对象，传递当前对象副本避免引用冲突
      result = result.concat(flattenToArray(value, newKey, {...currentObj}));
    } else {
      // 处理基础类型值，生成包含所有已收集字段的新对象
      const newObj = {...currentObj};
      newObj[newKey] = value;
      result.push(newObj);
    }
  }

  // 处理空对象等边界场景，确保返回有效对象
  if (result.length === 0) {
    result.push({...currentObj});
  }

  return result;
}

// 测试输入
const input = {
  name: "Benny",
  department: {
    section: "Technical",
    branch: {
      timezone: "UTC",
    },
  },
  company: [
    {
      name: "SAP",
      customers: ["Ford-1", "Nestle-1"],
    },
    {
      name: "SAP",
      customers: ["Ford-2", "Nestle-2"],
    },
  ],
};

// 执行并输出结果
console.log(JSON.stringify(flattenToArray(input), null, 2));

输出结果 #

执行上述代码后，将得到期望的数组形式：

[
  {
    "name": "Benny",
    "department.section": "Technical",
    "department.branch.timezone": "UTC",
    "company.name": "SAP",
    "company.customers": "Ford-1"
  },
  {
    "name": "Benny",
    "department.section": "Technical",
    "department.branch.timezone": "UTC",
    "company.name": "SAP",
    "company.customers": "Nestle-1"
  },
  {
    "name": "Benny",
    "department.section": "Technical",
    "department.branch.timezone": "UTC",
    "company.name": "SAP",
    "company.customers": "Ford-2"
  },
  {
    "name": "Benny",
    "department.section": "Technical",
    "department.branch.timezone": "UTC",
    "company.name": "SAP",
    "company.customers": "Nestle-2"
  }
]

代码说明 #

• 递归遍历：通过递归处理嵌套对象和数组，确保所有层级的字段都能被正确展平
• 数组处理：遇到数组时，对每个元素单独递归，将每个元素的展开结果与上层字段合并，实现多行生成
• 引用隔离：使用对象扩展运算符（...currentObj）创建副本，避免递归过程中修改原对象导致的字段污染
• 边界处理：针对空对象等场景，确保返回至少一个包含已收集字段的对象，避免结果为空

内容的提问来源于stack exchange，提问作者Benny