get all Objects inside an array of objects

Question

I am new to reactjs and javascript as well.

Here, I have an array of object which is like ,

[
  {
    "id": "CSS",
    "questionCount": [
      {
        "level": "TOUGH",
        "type": "NON_CODE",
        "count": "1"
      }
    ]
  },
  {
    "id": "Backbone",
    "questionCount": [
      {
        "level": "TOUGH",
        "type": "CODE",
        "count": "2"
      },
      {
        "level": "TOUGH",
        "type": "NON_CODE",
        "count": "5"
      },
      {
        "level": "MEDIUM",
        "type": "NON_CODE",
        "count": "7"
      },
      {
        "level": "EASY",
        "type": "NON_CODE",
        "count": "6"
      }
    ]
  },
]

Now, here what I want is to have an array of object which will have all the objects that are present in the questionCount array. so, it will be like ,

[  {
        "level": "TOUGH",
        "type": "NON_CODE",
        "count": "1"
      },  {
        "level": "TOUGH",
        "type": "CODE",
        "count": "2"
      },
      {
        "level": "TOUGH",
        "type": "NON_CODE",
        "count": "5"
      },
      {
        "level": "MEDIUM",
        "type": "NON_CODE",
        "count": "7"
      },
      {
        "level": "EASY",
        "type": "NON_CODE",
        "count": "6"
      } ]

So, can any one help me with this ?

Answer 1

You can use Array.prototype.reduce() with Array.prototype.concat() :

 const temp = [{"id": "CSS","questionCount": [{"level": "TOUGH","type": "NON_CODE","count": "1"}]},{"id": "Backbone","questionCount": [{"level": "TOUGH","type": "CODE","count": "2"},{"level": "TOUGH","type": "NON_CODE","count": "5"},{"level": "MEDIUM","type": "NON_CODE","count": "7"},{"level": "EASY","type": "NON_CODE","count": "6"}]},]; const result = temp.reduce((a, c) => a.concat(c.questionCount), []); console.log(result); 

Answer 2

You can iterate through each element and concatenate it with result. Try with the followings:

 var jsonObject = [{"id": "CSS","questionCount": [{"level": "TOUGH","type": "NON_CODE","count": "1"}]},{"id": "Backbone","questionCount": [{"level": "TOUGH","type": "CODE","count": "2"},{"level": "TOUGH","type": "NON_CODE","count": "5"},{"level": "MEDIUM","type": "NON_CODE","count": "7"},{"level": "EASY","type": "NON_CODE","count": "6"}]}] var result = []; for(var t of jsonObject){ if(t.questionCount){ //As t.questionCount is an array, we need to add property to each of the element present in that array t.questionCount.forEach(obj => obj.Id = t.id); result = result.concat(t.questionCount); } } console.log(result); 

Answer 3

Lets say temp is given array, then you can can array of questionCount using following code:-

finalArr=[]
for(var i=0;i<temp.length;i++) 
    finalArray.push(temp[i].questionCount)

Answer 4

This little peace of code will do it

var newData = [];
for (var i of data) {
  newData = newData.concat(i['questionCount'])
}

Answer 5

With ES6 reduce and spread, you can do something like this

 const x = arr.reduce((accum, curr) => { let newArr = [...accum, ...curr.questionCount]; return newArr }, []) 

Answer 6

// -- Use the swiss-knife-tool :-) (Lodash)
// -- Taking x as your array in the question, 
// -- you can use lodash to map specific attribute 
// -- and then flatten the output array.

const y = _
  .chain(x)
  .map(item => item.questionCount)
  .flatten()
  .value();

console.log(y);