Find type of elements contained in an array javascript

Question

I want to know about some function (if any) or library which may provide direct functions to find the type of elements in an array.

Suppose I have an array containing elements of same data type :

var sameArray = [1, 2, 3, 4];
var diffArray = ['a', 'b', 'c', 4];

sameArray.itemPrototype();  // Returns int
diffArray.itemPrototype();  // Returns undefined

For first array, it should return int and for the second one undefined or false.

Its just a dummy name. I haven't made any implementation yet. And I will prefer using a in-built function in some existing library. — Saba
– Saba, Commented Apr 6, 2015 at 7:04
Ok..For first one, expected output should be int, but as second case have multiple types present, so expected output should be undefined as you mentioned..Right? If thats the case, you can simply write a custom function, probably using typeof inside it.. — Rakesh_Kumar
– Rakesh_Kumar, Commented Apr 6, 2015 at 7:23

Kiril · Accepted Answer · 2015-04-06 09:25:41Z

2

For arrays with primitives (like numbers, strings) you may use a simple method:

function getItemsType(arr) {
  var itemType, i;

  for (i=0; i < arr.length; i++) {
    if (typeof itemType === 'undefined') {
      itemType = typeof arr[i];
    } else if (itemType !== typeof arr[i]) {
      return undefined;
    }
  }

  return itemType;
}

In this jsbin you'll find a function implementation and integration into Array.prototype.

answered Apr 6, 2015 at 9:25

Kiril

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