How to remove duplicates from object using javascript

Question

My object is like this.

var myData = [
   { 123: 1}, 
   { 123: 2}, 
   { 124: 3}, 
   { 124: 4}
];

and the expected result is:

var myDataNew = [
    {123: [1, 2]}, 
    {124: [3,4]}
];

How to achieve this using javascript?

There is no JSON in your question, just JavaScript, and you are trying to remove objects from an array. — Quentin
– Quentin, Commented Oct 17, 2018 at 10:31
Can you improve your question title then? What you're looking for is a reducer. What have you attempted so far? — Christopher Moore
– Christopher Moore, Commented Oct 17, 2018 at 10:33

Alex G · Accepted Answer · 2018-10-17 10:56:13Z

1

You can try this, with your current structure, where each object in the myData array has only one member.

const myData = [
    { 123: 1},
    { 123: 2},
    { 124: 3},
    { 124: 4}
];

const groupDuplicates = (arr) =>
    
    arr.reduce((acc, val) => {
        
        const key = Object.keys(val).toString();
        
        const item = acc.find((item) => Object.keys(item).toString() === key);

        if (!item) acc.push({ [key]: [val[key]]});

        else item[key].push(val[key]);

        return acc;
    }, []);

console.log(groupDuplicates(myData));

answered Oct 17, 2018 at 10:56

Alex G

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protoproto · Accepted Answer · 2018-10-17 11:00:40Z

You can use this code:

var myData = [
               { 123: 1}, 
               { 123: 2}, 
               { 124: 3}, 
               { 124: 4}
             ];
/*
var myDataNew = [
    {123: [1, 2]}, 
    {124: [3,4]}
];
            */
var keys = myData.map(current=>Object.keys(current)[0]);
//console.log(keys);//(4) ["123", "123", "124", "124"]
var result = [];
keys.forEach((current,index)=>{
  //findIndex in result
  let id = result.findIndex(c=>{
    if(c[current])
      return c;
  });
  // not find
  if(id===-1){
    let obj = {};
    obj[current] = [myData[index][current]];
    result.push(obj);
  // find, let push
  }else{
    result[id][current].push(myData[index][current]);
  }
});
console.log(result);

brk · Accepted Answer · 2018-10-17 11:05:44Z

0

First use reduce function to create an object then loop over it & in new array push the value

var myData = [{
    123: 1
  },
  {
    123: 2
  },
  {
    124: 3
  },
  {
    124: 4
  }
];


let k = myData.reduce(function(acc, curr) {
  let getKey = Object.keys(curr)[0];// get the key
  let getVal = Object.values(curr)[0] //get the value
  //check if key like 123,124 exist in object
  if (!acc.hasOwnProperty(getKey)) { 
    acc[getKey] = [getVal]
  } else {
    acc[getKey].push(getVal)
  }
  return acc;

}, {})
let newArray = [];
for (let keys in k) {
  newArray.push({
    [keys]: k[keys]
  })
}
console.log(newArray)

answered Oct 17, 2018 at 11:05

brk

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