You have to create an object. Assign the values to the object. Then push it into the array:

var nietos = [];
var obj = {};
obj["01"] = nieto.label;
obj["02"] = nieto.value;
nietos.push(obj);

You want the splice function on the native array object.

arr.splice(index, 0, item); will insert item into arr at the specified index (deleting 0 items first, that is, it's just an insert).

In this example we will create an array and add an element to it into index 2:

var arr = [];
arr[0] = "Jani";
arr[1] = "Hege";
arr[2] = "Stale";
arr[3] = "Kai Jim";
arr[4] = "Borge";

console.log(arr.join()); // Jani,Hege,Stale,Kai Jim,Borge
arr.splice(2, 0, "Lene");
console.log(arr.join()); // Jani,Hege,Lene,Stale,Kai Jim,Borge

UPDATE (24 May 2024)

You can now use the toSpliced method which behaves just like splice, however it returns a new array without mutating the existing one.

You could update the previous example like so:

const updated = arr.toSpliced(2, 0, "Lene");

Object is a reference type, so you can get the target object from the array by index and then update its newArr property.

let arr = [{
  name: {
    "id": 1
  },
  data: {
    "dataVal": 'value1'
  }
}, {
  name: {
    "id": 2
  },
  data: {
    "dataVal": 'value2'
  }
}, {
  name: {
    "id": 3
  },
  data: {
    "dataVal": 'value3'
  }
}]




const update = (array, index, property, value) => {
  array[index][property] = value;
}

update(arr, 0, "newArr", [])

console.log(arr);