如何遍历JSON对象定位特定属性并将其内容推送到数组？ [英] How to traverse JSON object locating particular property and pushing its contents to array?

问题描述

我正在使用一个JSON对象，它可以在任何叶子上有一个属性 ids 。我想遍历该对象并找到 ids 属性的所有实例，并将每个id存储在一个集合中。

I am working with a JSON object which can have a property ids at any leaf. I want to traverse the object and find all of the instances of the ids property and store each id in a collection.

模拟JSON对象（ ids 属性可能位于更深的属性位置。）

Mocked up JSON Object (the ids property could be at much deeper property locations).

{
  "id": "b38a683d-3fb6-408f-9ef6-f4b853ed1193",
  "foo": {
    "ids": [
      {
        "id": "bd0bf3bd-d6b9-4706-bfcb-9c867e47b881"
      },
      {
        "id": "d1cc529d-d5d2-4460-b2bb-acf24a7c5999"
      },
      {
        "id": "b68d0c8c-548e-472f-9b01-f25d4b199a71"
      }
    ],
    "baz": "super"
  },
  "bar": {
    "ids": [
      {
        "id": "bd0bf3bd-d6b9-4706-bfcb-9c867e47b881"
      },
      {
        "id": "d1cc529d-d5d2-4460-b2bb-acf24a7c5999"
      },
      {
        "id": "b68d0c8c-548e-472f-9b01-f25d4b199a71"
      }
    ]
  }
}

我使用以下代码遍历上面的代码JSON。

I am using the following code to traverse the above JSON.

var jsonFile = require('./file_test.json'); // the above in my local directory

function traverse(obj, ids) {
  for (var prop in obj) {
    if (typeof obj[prop] == "object" && obj[prop]) {
      if (prop == 'ids') {
        for (var i = obj[prop].length - 1; i >= 0; i--) {
          ids.push(obj[prop][i]._id);
        };
      }
      traverse(obj[prop], ids);
    }
  }
}

var ids = new Array();
traverse(jsonFile, ids);

console.log('ids', ids);

上述网络如下：

ids
[
  'b68d0c8c-548e-472f-9b01-f25d4b199a71',
  'd1cc529d-d5d2-4460-b2bb-acf24a7c5999',
  'bd0bf3bd-d6b9-4706-bfcb-9c867e47b881',
  'b68d0c8c-548e-472f-9b01-f25d4b199a71',
  'd1cc529d-d5d2-4460-b2bb-acf24a7c5999',
  'bd0bf3bd-d6b9-4706-bfcb-9c867e47b881'
]

当我的代码工作时，我不相信我这样做是最有效或最好的方式。有没有更好的方法来查找 ids 属性的所有实例？也许没有传入一个数组但返回一个？或者使用 ids 数组设置回调？

While my code works I am not convinced that I am doing this the most efficient or best way. Is there a better way to find all instances of the ids property? Perhaps without passing in an array but returning one? Or setting up for a callback with an ids array?

推荐答案

什么你没问题，但这有点短，并使用.map函数：

what you have is fine, but this is a little shorter and uses the .map function:

var jsonFile = require('./file_test.json'); // the above in my local directory
function traverse(obj) {
    var ids = [];
    for (var prop in obj) {
        if (typeof obj[prop] == "object" && obj[prop]) {
            if (prop == 'ids') {
                ids = obj[prop].map(function(elem){
                   return elem.id;
               })
            }
            ids =ids.concat(traverse(obj[prop]));
        }
    }
    return ids;
}

var ids =traverse(jsonFile);

console.log('ids', ids);

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