JSON对象中的递归数据

Question

{
"groups": [
    {
        "name": "Event",
        "groups": [
            {
                "name": "Service",
                "subscriptions": [
                    {
                        "topic": "SERVICE_STATUS_PRESETS"
                    },
                    {
                        "topic": "AIRCRAFT_ACTIVATION",

                    },
                    {
                        "topic": "OUT_OF_SERVICE",

                    }
                ]
            }
        ]
    },
    {
        "name": "Enquiries",
        "groups": [
            {
                "name": "Service-related",
                "subscriptions": [
                    {

                        "topic": "PROMO_CODES_REQUESTS",

                    }
                ]
            }
        ]
    }
],
"subscriptions": [
    {
        "topic": "BANNERS",
    },
    {
        "topic": "DOCUMENTS",
    },
    {
        "topic": "USER",
    }
]

}

好的，伙计们，我有这样的 JSON 结构，我需要的是：返回数组中的所有主题，在这个例子中它将是：

[“SERVICE_STATUS_PRESETS”、“AIRCRAFT_ACTIVATION”、“OUT_OF_SERVICE”、“PROMO_CODES_REQUESTS”、“BANNERS”、“DOCUMENTS”、“USER”]

我尝试这样的递归调用，虽然我只得到最后三个记录：

getRecursive() {
if (Array.isArray(data)) {
       for (let i = 0; i < data.length; i++) {
         if (data[i].subscriptions) {
           return data[i].subscriptions.map((val: SubscriptionGroupDetails) => val.topic);
         } else if (data[i].groups) {
           return this.getAllTopics(data[i].groups);
         }
       }
     }
     if (data && data.groups) {
      return this.getAllTopics(data.groups);
     }
     return data.subscriptions.map((val: SubscriptionGroupDetails) => val.topic);
}

Answer 1

您可以采用递归方法并检查

• 如果传递过来的数据不是检查对象，则返回空数组，
• 如果对象有想要的属性，则返回一个值为topic的数组，
• 或获取值并使用函数进行递归调用，并返回一个包含结果的数组。

function getTopics(object) {
    if (!object || typeof object !== 'object') return [];
    if ('topic' in object) return [object.topic];
    return Object.values(object).reduce((r, v) => [...r, ...getTopics(v)], []);
}

var data = { groups: [{ name: "Event", groups: [{ name: "Service", subscriptions: [{ topic: "SERVICE_STATUS_PRESETS" }, { topic: "AIRCRAFT_ACTIVATION" }, { topic: "OUT_OF_SERVICE" }] }] }, { name: "Enquiries", groups: [{ name: "Service-related", subscriptions: [{ topic: "PROMO_CODES_REQUESTS" }] }] }], subscriptions: [{ topic: "BANNERS" }, { topic: "DOCUMENTS" }, { topic: "USER" }] },
    result = getTopics(data);

console.log(result);

Answer 2

这是使用object-scan的解决方案

// const objectScan = require('object-scan');

const data = {"groups":[{"name":"Event","groups":[{"name":"Service","subscriptions":[{"topic":"SERVICE_STATUS_PRESETS"},{"topic":"AIRCRAFT_ACTIVATION"},{"topic":"OUT_OF_SERVICE"}]}]},{"name":"Enquiries","groups":[{"name":"Service-related","subscriptions":[{"topic":"PROMO_CODES_REQUESTS"}]}]}],"subscriptions":[{"topic":"BANNERS"},{"topic":"DOCUMENTS"},{"topic":"USER"}]};

const searchTopics = (obj) => objectScan(['**.topic'], { rtn: 'value' })(obj);

console.log(searchTopics(data));
/* => [
  'USER',
  'DOCUMENTS',
  'BANNERS',
  'PROMO_CODES_REQUESTS',
  'OUT_OF_SERVICE',
  'AIRCRAFT_ACTIVATION',
  'SERVICE_STATUS_PRESETS'
] */

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

<script src="https://bundle.run/object-scan@13.7.1"></script>

免责声明：我是object-scan的作者

Answer 3

如果您有兴趣，此版本将采用功能方法。上面还有其他的，但这只是另一种看待它的方式。

const recursion = object => Object.entries(object).map(([a, b]) => {
  if (a === 'topic') return b;
  if (Array.isArray(b)) return b.map(recursion);
  return [];
}).flat(Infinity);

recursion(obj);

Answer 4

编辑：添加了另一种使用 .reduce()

的方法

您可以创建一个topics 的空数组，然后递归地浏览嵌套结构，每次遇到它时添加一个主题，使用javascript .forEach() 循环浏览任何嵌套的groups 或subscriptions .

let topics = [];

let findTopics = obj => {
   if (obj.groups) {
      obj.groups.forEach(findTopics);
   }
   if (obj.subscriptions) {
      obj.subscriptions.forEach(findTopics);
   }
   if (obj.topic) {
      topics.push(obj.topic);
   }
}

findTopics(data);

或者使用.reduce() 的一种可能更简洁的方式：

let findTopicsRecursive = (topics, obj) => {
   if (obj.groups) {
      topics = obj.groups.reduce(findTopicsRecursive, topics);
   }
   if (obj.subscriptions) {
      topics = obj.subscriptions.reduce(findTopicsRecursive, topics);
   }
   if (obj.topic) {
      topics.push(obj.topic);
   }
   return topics;
}

let findTopics = data => findTopicsRecursive([], data);

let topics = findTopics(data);

Answer 5

使用这个：

function getTopics(obj){
   if(typeof obj !== 'object') return [];
   if(obj.topic) return [obj.topic];
   var res = [];
   for(var i in obj){
     res.push(...getTopics(obj[i]));
   }
   return res;
}

工作示例：

const topics = {
"groups": [
    {
        "name": "Event",
        "groups": [
            {
                "name": "Service",
                "subscriptions": [
                    {
                        "topic": "SERVICE_STATUS_PRESETS"
                    },
                    {
                        "topic": "AIRCRAFT_ACTIVATION",

                    },
                    {
                        "topic": "OUT_OF_SERVICE",

                    }
                ]
            }
        ]
    },
    {
        "name": "Enquiries",
        "groups": [
            {
                "name": "Service-related",
                "subscriptions": [
                    {

                        "topic": "PROMO_CODES_REQUESTS",

                    }
                ]
            }
        ]
    }
],
"subscriptions": [
    {
        "topic": "BANNERS",
    },
    {
        "topic": "DOCUMENTS",
    },
    {
        "topic": "USER",
    }
]
}

function getTopics(obj){
  if(typeof obj !== 'object') return [];
  if(obj.topic) return [obj.topic];
  var res = [];
  for(var i in obj){
    res.push(...getTopics(obj[i]));
  }
  return res;
}


console.log(getTopics(topics));