Convert array to nested object structure using Javascript

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 i.e- 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.

Mohammad Hooshdar · Accepted Answer · 2022-04-22 09:43:02Z

2

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)

edited Apr 22, 2022 at 9:43

answered Apr 22, 2022 at 8:33

Mohammad Hooshdar

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3 Comments

Rickard Elimää Over a year ago

Upvoting this, because you did a sort, instead of assuming that you will get the correct order from the server.

subhra_user Over a year ago

@Mohammad: Its a good solution but found one issue. I add some more keys to each object like this for(let e of data) { Object.assign(e, {ip: "", port: 22, user: "", password: "", "device-type": "linux"}); } but its not reflecting along with other two keys in each nested and parent object.

Mohammad Hooshdar Over a year ago

@subhra_user Yes, you are right, I edited the script, and you can check it out now.

luko · Accepted Answer · 2022-04-22 08:16:13Z

0

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);

edited Apr 22, 2022 at 8:16

answered Apr 22, 2022 at 7:48

luko

794 bronze badges

2 Comments

subhra_user Over a year ago

We dont need next-hop in last object.

luko Over a year ago

i updated the script

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