Merge the values into an array based on their shared id within a JSON object

Question

Merge the values into an array based on their shared id within a JSON object

Is it possible to map JSON objects with duplicate id values to their association property in an array using JavaScript after a join operation?

{
    "id": 1,
    "name": "doc 1",
    "appointmentTime": "2018-12-28T00:00:43"
},

{
    "id": 2,
    "name": "doc 2",
    "appointmentTime": "2018-12-25T23:00:53"
},
{
    "id": 2,
    "name": "doc 2",
    "appointmentTime": "2018-12-26T23:00:02"
},
{
    "id": 3,
    "name": "doc3",
    "appointmentTime": null
},

Desired output:

{
    "id": 1,
    "name": "doc1",
    "appointmentTime": ["2018-12-28T00:00:43"]
},
{
        "id": 2,
        "name": "doc 2",
        "appointmentTime": ["2018-12-26T23:00:02","2018-12-26T23:00:02"]
    },
    {
        "id": 3,
        "name": "doc3",
        "appointmentTime": null
    },

javascript json object

Answer 1

Answer №1

To accomplish this task, you should utilize the reduce function:

const data = [{
    "id": 1,
    "name": "document 1",
    "createdTime": "2018-12-28T00:00:43"
},

{
    "id": 2,
    "name": "document 2",
    "createdTime": "2018-12-25T23:00:53"
},
{
    "id": 2,
    "name": "document 2",
    "createdTime": "2018-12-26T23:00:02"
},
{
    "id": 3,
    "name": "document 3",
    "createdTime": null
}]

const output = data.reduce((acc, {id, name, createdTime}) => {
  const found = acc.find(item => item.id === id)
  if (found) { found.createdTime.push(createdTime) } 
  else {acc.push({id, name, createdTime: [createdTime]})}
  
  return acc
}, [])

console.log(output)

I have also incorporated the destructuring assignment

Answer 2

To accomplish this task, you should utilize the reduce function:

const data = [{
    "id": 1,
    "name": "document 1",
    "createdTime": "2018-12-28T00:00:43"
},

{
    "id": 2,
    "name": "document 2",
    "createdTime": "2018-12-25T23:00:53"
},
{
    "id": 2,
    "name": "document 2",
    "createdTime": "2018-12-26T23:00:02"
},
{
    "id": 3,
    "name": "document 3",
    "createdTime": null
}]

const output = data.reduce((acc, {id, name, createdTime}) => {
  const found = acc.find(item => item.id === id)
  if (found) { found.createdTime.push(createdTime) } 
  else {acc.push({id, name, createdTime: [createdTime]})}
  
  return acc
}, [])

console.log(output)

I have also incorporated the destructuring assignment

Answer 3

Answer №2

> const combineDuplicates = (arr, key, mergeKey) => {
>     const hashMap = {}; 
>     arr.forEach(item => {
>         if(hashMap[item[key]] === null) { 
>             item[mergeKey] = [item[mergeKey]]; 
>             hashMap[item[key]] = item;  
>         }
>         else { 
>             hashMap[item[key]][mergeKey].push(item[mergeKey]); 
>         }
>
>         const combinedArr = [];
>         for(let uniqueKey in hashMap) {
>             combinedArr.push(hashMap[uniqueKey]);
>         }
>         return combinedArr;
>     });
> }
> updatedArray = combineDuplicates(updatedArray, "identifier", "timeOfEvent");

Answer 4

> const combineDuplicates = (arr, key, mergeKey) => {
>     const hashMap = {}; 
>     arr.forEach(item => {
>         if(hashMap[item[key]] === null) { 
>             item[mergeKey] = [item[mergeKey]]; 
>             hashMap[item[key]] = item;  
>         }
>         else { 
>             hashMap[item[key]][mergeKey].push(item[mergeKey]); 
>         }
>
>         const combinedArr = [];
>         for(let uniqueKey in hashMap) {
>             combinedArr.push(hashMap[uniqueKey]);
>         }
>         return combinedArr;
>     });
> }
> updatedArray = combineDuplicates(updatedArray, "identifier", "timeOfEvent");

Answer 5

Answer №3

This is my approach:

    //Assuming you have jsonObj stored in an Array like this:
var myarray = [{
    "id": 1,
    "name": "doc 1",
    "appointmentTime": "2018-12-28T00:00:43"
  },
  {
    "id": 2,
    "name": "doc 2",
    "appointmentTime": "2018-12-25T23:00:53"
  },
  {
    "id": 2,
    "name": "doc 2",
    "appointmentTime": "2018-12-26T23:00:02"
  },
  {
    "id": 3,
    "name": "doc3",
    "appointmentTime": null
  }
];

//Iterate through the data to combine duplicates
for (var i = 0; i < myarray.length; i++) {
  //Check for duplicate data
  for (var j = i + 1; j < myarray.length; j++) {
    if (myarray[i].id == myarray[j].id) {
      var tmp = myarray[j].appointmentTime;
      myarray[j].appointmentTime = [];
      myarray[j].appointmentTime.push(tmp);
      myarray[j].appointmentTime.push(myarray[i].appointmentTime);

      myarray[i] = {};
    }
  }
}
console.log(myarray);

Finally, remove any empty JSON objects.

https://jsfiddle.net/m073qwr6/1/

Answer 6

This is my approach:

    //Assuming you have jsonObj stored in an Array like this:
var myarray = [{
    "id": 1,
    "name": "doc 1",
    "appointmentTime": "2018-12-28T00:00:43"
  },
  {
    "id": 2,
    "name": "doc 2",
    "appointmentTime": "2018-12-25T23:00:53"
  },
  {
    "id": 2,
    "name": "doc 2",
    "appointmentTime": "2018-12-26T23:00:02"
  },
  {
    "id": 3,
    "name": "doc3",
    "appointmentTime": null
  }
];

//Iterate through the data to combine duplicates
for (var i = 0; i < myarray.length; i++) {
  //Check for duplicate data
  for (var j = i + 1; j < myarray.length; j++) {
    if (myarray[i].id == myarray[j].id) {
      var tmp = myarray[j].appointmentTime;
      myarray[j].appointmentTime = [];
      myarray[j].appointmentTime.push(tmp);
      myarray[j].appointmentTime.push(myarray[i].appointmentTime);

      myarray[i] = {};
    }
  }
}
console.log(myarray);

Finally, remove any empty JSON objects.

https://jsfiddle.net/m073qwr6/1/

Merge the values into an array based on their shared id within a JSON object

Answer №1

Answer №2

Answer №3

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