如何将JSON嵌套对象聚合到其父对象的相邻下一位？

需求说明 #

给定包含嵌套disclosures数组的JSON数组，需将每个父对象保留（移除disclosures属性），并将其disclosures中的每个对象依次插入到父对象的紧邻下一位，最终得到无嵌套的一维数组，且严格保持原顺序（父对象在前，对应嵌套对象紧随其后）。

原始JSON数组 #

[
   {
      "questionText":"some text 1",
      "answerText":"some text"
   },{
      "questionText":"some text 2",
      "answerText":"some text"
   },{
      "questionText":"some text 3",
      "answerText":"some text",
      "disclosures":[
         {
            "questionText":"some text 4",
            "answerText":"some text"
         },{
            "questionText":"some text 5",
            "answerText":"some text"
         }
      ]
   },{
      "questionText":"some text 6",
      "answerText":"some text"
   },{
      "questionText":"some text 7",
      "answerText":"some text",
      "disclosures":[
         {
            "questionText":"some text 8",
            "answerText":"some text"
         }
      ]
   }
]

目标JSON数组 #

[
   {
      "questionText":"some text 1",
      "answerText":"some text"
   },{
      "questionText":"some text 2",
      "answerText":"some text"
   },{
      "questionText":"some text 3",
      "answerText":"some text"
   },{
      "questionText":"some text 4",
      "answerText":"some text"
   },{
      "questionText":"some text 5",
      "answerText":"some text"
   },{
      "questionText":"some text 6",
      "answerText":"some text"
   },{
      "questionText":"some text 7",
      "answerText":"some text"
   },{
      "questionText":"some text 8",
      "answerText":"some text"
   }
]

解决方案 #

使用JavaScript的flatMap方法可以实现需求，它能遍历数组并将每个元素映射为新数组，最后自动展开为一维数组。具体逻辑如下：

1. 遍历原始数组的每个元素；
2. 对包含disclosures的元素，先复制该元素并移除disclosures属性，再将处理后的父对象和disclosures中的所有对象组成新数组；
3. 对不包含disclosures的元素，直接将其放入单元素数组；
4. flatMap自动将所有子数组展开为最终的一维数组。

代码实现 #

const originalArray = [
  {"questionText":"some text 1","answerText":"some text"},
  {"questionText":"some text 2","answerText":"some text"},
  {"questionText":"some text 3","answerText":"some text","disclosures":[{"questionText":"some text 4","answerText":"some text"},{"questionText":"some text 5","answerText":"some text"}]},
  {"questionText":"some text 6","answerText":"some text"},
  {"questionText":"some text 7","answerText":"some text","disclosures":[{"questionText":"some text 8","answerText":"some text"}]}
];

const transformedArray = originalArray.flatMap(item => {
  // 复制父对象并移除disclosures属性
  const parentItem = {...item};
  delete parentItem.disclosures;
  // 根据是否有disclosures返回对应数组
  return item.disclosures ? [parentItem, ...item.disclosures] : [parentItem];
});

// 输出格式化后的结果
console.log(JSON.stringify(transformedArray, null, 3));

说明 #

• 该方法严格保持原顺序：父对象在前，其disclosures中的对象按原顺序紧随其后；
• 使用对象展开运算符{...item}复制父对象，避免修改原始数据；
• flatMap替代普通map，解决了普通map会将嵌套数组保留在结果中的问题，自动完成数组展开。

内容的提问来源于stack exchange，提问作者mhery