如何针对特定键递归迭代嵌套的 object

Question

我正在尝试编写一个递归的 function，它本质上是向下钻取 object 以寻找特定的键。 找到该密钥后，我想重命名该 object 密钥并保留原始内容并继续遍历该找到的密钥的值（对象数组）以查找相同的密钥（如果存在）。

const data = {
   "name": "lorem",
   "folders": [
      {
         "name": "ipsum",
         "folders": [
            {
               "name": "inner ipsum",
               "folders": [
                   {
                      "name": "first nested"
                   },
                   {
                      "name": "second nested" 
                   }
               ]
            }
         ]
      },
      {
         "name": "dolor",
         "folders": [
            {
               "name": "first inner dolor"
            },
            {
               "name": "second inner dolor",
               "folders": [
                  {
                     "name": "test"
                  }
               ]
            }
         ]
      }
   ]
   
}

// recursive function that looks for key === "folders" within obj and renames to "items"
// continues to search within "items" value for the same "folders" key to repeat the process of // renaming the obj

const recursivelyGetAllFolders = (obj) => {
   for (const key in obj) {
      if (obj.hasOwnProperty(key)) {
        if (key === "folders") {
          // keep contents of folders obj, but rename key to "items"
          obj["items"] = obj["folders"];

          // call function recursively to iterate through again?
          if (obj["items"] && typeof obj["items"] === "object") {
            const result = recursivelyGetAllFolders(folder["items"]);
            if (result) {
               return result;
            }
          } else {
              return obj;
          }
        }
      }
    }
}

recursivelyGetAllFolders(data);

Answer 1

您不必遍历 object 的键。您只需要

• 检查 object 是否有folders键并将其重命名为items 。
• 然后在items中的每个 object上递归调用 function（您递归调用items数组本身而不是数组中的每个 object）

function recursivelyUpdateFolders(obj) {
  if (obj.hasOwnProperty("folders")) {
    obj.items = obj.folders
    delete obj.folders
    obj.items?.forEach(recursivelyUpdateFolders)
  }
  return obj
}

这是一个片段：

 const data={name:"lorem",folders:[{name:"ipsum",folders:[{name:"inner ipsum",folders:[{name:"first nested"},{name:"second nested"}]}]},{name:"dolor",folders:[{name:"first inner dolor"},{name:"second inner dolor",folders:[{name:"test"}]}]}]}; function recursivelyUpdateFolders(obj) { if (obj.hasOwnProperty("folders")) { obj.items = obj.folders delete obj.folders obj.items?.forEach(recursivelyUpdateFolders) } return obj } console.log( recursivelyUpdateFolders(data) )

Answer 2

我们可以退一步，将“folders”和“items”参数做成function。这样不会让我们的代码变得更难，反而会更灵活。

此版本不会改变您的原始版本（我们不是野蛮人，对吧？），但会返回应用了更改的副本。

 const renameNestedKey = (source, target) => (o) => Array.isArray (o)? o.map (renameNestedKey (source, target)): Object (o) === o? Object.fromEntries (Object.entries (o).map ( ([k, v]) => [k == source? target: k, renameNestedKey (source, target) (v)] )): o const data = {name: "lorem", folders: [{name: "ipsum", folders: [{name: "inner ipsum", folders: [{name: "first nested"}, {name: "second nested"}]}]}, {name: "dolor", folders: [{name: "first inner dolor"}, {name: "second inner dolor", folders: [{name: "test"}]}]}]} console.log (renameNestedKey ('folders', 'items') (data))

 .as-console-wrapper {max-height: 100%;important: top: 0}

我们的 function 获取源键名和目标键名，并返回一个 function，它接受一个输入 object。当输入是一个数组时，它map会覆盖该数组。 当输入是 object 时，我们将其分解为键值对，然后将其分解为 map，必要时转换键，并在值上重复，然后将键值对的结果集放回 object。输入既不是数组也不是 object，我们只是返回它。