JavaScript merge array objects with the same keys-CodePudding

I have an array with several objects some have the same keys (Question and QuestionId), for example:

    var jsonData = [
            {
                Question: "Was the training useful?",
                QuestionId: 1,
                myData: [{ name: 'No', value: 1 }] },
            {
                Question: "Was the training useful?",
                QuestionId: 1 ,
                myData: [{ name: 'Yes', value: 1 }]
        }];

How can I combine these objects into one, expected output:

      var jsonData = [
        {
            Question: "Was the training useful?",
            QuestionId: 1,
            myData: [{ name: 'No', value: 1 },
                     { name: 'Yes', value: 1 }] 
          }];

CodePudding user response：

var jsonData = [{
    Question: "Was the training useful?",
    QuestionId: 1,
    myData: [{
      name: 'No',
      value: 1
    }]
  },
  {
    Question: "Was the training useful?",
    QuestionId: 1,
    myData: [{
      name: 'Yes',
      value: 1
    }]
  }
];

const result = Object.values(jsonData.reduce((acc, obj) => {
  if (!acc[obj.QuestionId]) {
    acc[obj.QuestionId] = obj;
  } else {
    acc[obj.QuestionId].myData = acc[obj.QuestionId].myData.concat(obj.myData);
  }
  return acc;
}, {}));

console.log(result);

CodePudding user response：

function mergeData(data) {
  const acc = {}
  data.forEach(x => {
    const id = x.QuestionId
    if (!acc[id]) acc[id] = x
    else acc[id].myData = acc[id].myData.concat(x.myData)
  })
  return Object.values(acc)
}

CodePudding user response：

You can use forEach to create an object where the keys are the question IDs and then use forEach again on Object.keys to transfer the values from that object to a new array.

var jsonData = [{
  Question: "Was the training useful?",
  QuestionId: 1,
  myData: [{ name: 'No', value: 1 }] 
}, {
  Question: "Was the training useful?",
  QuestionId: 1 ,
  myData: [{ name: 'Yes', value: 1 }]
}];

var temp = {};
jsonData.forEach(x=>{
  if(!temp[x.QuestionId]) {temp[x.QuestionId] = x;} 
  else {temp[x.QuestionId].myData.push(x.myData);}
});

var arr = [];
Object.keys(temp).forEach(x=>{arr.push(temp[x]);});

console.log(arr);