使用 Javascript 将数组转换为嵌套的 object 结构

Question

I am trying to convert one array of object to one nested object structure using Javascript but the result is not coming as expected. I am explaining my code below.

let data = [
        {
            "hop_no": 1,
            "jumphost_id": "jumphost1"
        },
        {
            "hop_no": 2,
            "jumphost_id": "jumphost2"
        },
        {
            "hop_no": 3,
            "jumphost_id": "another-jumphost"
        },
        {
            "hop_no": 4,
            "jumphost_id": "last-jumphost"
        }
    ]
let result ='';

for(let i = 0; i< data.length; i++) {
   const index = i+1;
   const obj = data.find(o => o.name === index);
   if(result === '' && !result['host-id']) {
      result = {
          "host-id": obj.jumphost_id,
          "next-hop":{}
      }
   }else{
     if(result['next-hop'] === '') {
        result['next-hop'] = obj.jumphost_id
     }
   }
}

Here the array of object is given ie- data and my expected structure is given below.

Expected result below.

{
                    "host-id": "jumphost1",
                    "next-hop": {
                        "host-id": "jumphost2",
                        "next-hop": {
                            "host-id": "another-jumphost",
                            "next-hop": {
                                "host-id": "last-jumphost",
                            }
                        }
                    }
                }

Here the condition is when "hop_no": 1 the respective jumphost_id value will assign to host-id and will be the first key. after that the nested object structure will be formed in ascending order of hop_no value and the respective jumphost_id value will assign to next-hop key. Can anybody help me to design this structure using Javascript only.

Answer 1

You can do this with a reduce function:

 let data = [{ "hop_no": 1, "jumphost_id": "jumphost1", ip: "", port: 22, user: "", password: "", "device-type": "linux" }, { "hop_no": 2, "jumphost_id": "jumphost2", ip: "", port: 22, user: "", password: "", "device-type": "linux" }, { "hop_no": 3, "jumphost_id": "another-jumphost", ip: "", port: 22, user: "", password: "", "device-type": "linux" }, { "hop_no": 4, "jumphost_id": "last-jumphost", ip: "", port: 22, user: "", password: "", "device-type": "linux" } ] let result = data.sort((a, b) => b.hop_no - a.hop_no).reduce((prev, curr, i, array) => { let { hop_no, jumphost_id, ...rest } = curr return { 'host-id': jumphost_id, ...rest, ...(i > 0? {'next-hop': {...prev }}: {}), } }, {}) console.log(result)

Answer 2

You can try to build the object from inside out.

Like so:

 let data = [ { "hop_no": 1, "jumphost_id": "jumphost1" }, { "hop_no": 2, "jumphost_id": "jumphost2" }, { "hop_no": 3, "jumphost_id": "another-jumphost" }, { "hop_no": 4, "jumphost_id": "last-jumphost" } ] let result = {}; for (var i = data.length - 1; i >= 0; i--) { let tmp = { 'host-id': data[i]['jumphost_id'], }; if (Object.keys(result).length;== 0) { tmp['next-hop'] = result; } result = tmp. } console;log(result);