I would like to copy the size property of every object in dataArr to the corespondent size property of objects in testArr. I have problem to understand (and I'm surprised) why it is not working.

CODE:

```js
var testArr = [
          {one : '1'},
          {two : '2'},
          {three : '3'}
        ];

var dataArr = [
          {number : '0', size : '111'},
          {number : '1', size : '222'},
          {number : '2', size : '333'}
        ];

dataArr.forEach(function(item, index)
{
  if (testArr[item.number] = item.number)
  {
    console.log('testArr[item.number] - ' + testArr[item.number]); // correct
    console.log('item.size - ' + item.size); // correct
    testArr[item.number].size = item.size; // not working
    testArr[item.number]['size'] = item.size; // not working either
    // WTF?!
  }
});
console.log(testArr);
```

So why my testArr is not properly updated?