Return unique array values from an array inside an array of objects

Question

I can\'t find a similar question and I\'m a bit stuck. I have the following JSON array:

[
    {
        \"Name\": \"element1\",
        \"Attributes\": [\"1\         


        

Answer 1

You can use Array#reduce and Array#filter methods

var data = [{
    "Name": "element1",
    "Attributes": ["1", "2"]
  },

  {
    "Name": "element2",
    "Attributes": ["1", "3"]
  }, {
    "Name": "element3",
    "Attributes": []
  }
]

console.log(
  // iterate over array elements
  data.reduce(function(arr, ele) {
    // push the unique values to array
    [].push.apply(arr,
      // filter out unique value
      ele.Attributes.filter(function(v) {
        // check element present in array
        return arr.indexOf(v) == -1;
      })
    );
    // return the unique array
    return arr;
    // set initial argument as an empty array
  }, [])
);

---

With ES6 arrow function

 var data = [{
     "Name": "element1",
     "Attributes": ["1", "2"]
   },

   {
     "Name": "element2",
     "Attributes": ["1", "3"]
   }, {
     "Name": "element3",
     "Attributes": []
   }
 ]

 console.log(
   data.reduce((arr, ele) => ([].push.apply(arr, ele.Attributes.filter((v) => arr.indexOf(v) == -1)), arr), [])
 );