How to form a JSON array using 1d array?

I am making fixed header table with vertical and horizontal scroll using a github project.

I am able to implement the basic template. Incase when I have some hidden table headers, I need to make some changes while passing the data to colModal of the function. I've made those changes. But I am unable to replicate(to match as in first fiddle) the data sent to colModal.

HTML

<table id="mytable">
  <thead>
    <tr>
      <th style="width:40px;display:none">Head1</th>
      <th style="width:50px">Head2</th>
      <th style="width:60px">Head3</th>
      <th style="width:70px">Head4</th>
      <th style="width:80px">Head5</th>
    </tr>
  </thead>
  <tbody>
    <tr>
      <td style="display:none">1</td>
      <td >2</td>
      <td >3</td>
      <td >4</td>
      <td >5</td>
    </tr>
       <tr>
      <td style="display:none">1</td>
      <td >2</td>
      <td >3</td>
      <td >4</td>
      <td >5</td>
    </tr>
       <tr>
      <td style="display:none">1</td>
      <td >2</td>
      <td >3</td>
      <td >4</td>
      <td >5</td>
    </tr>
       <tr>
      <td style="display:none">1</td>
      <td >2</td>
      <td >3</td>
      <td >4</td>
      <td >5</td>
    </tr>
       <tr>
      <td style="display:none">1</td>
      <td >2</td>
      <td >3</td>
      <td >4</td>
      <td >5</td>
    </tr>
  </tbody>
</table>

Jquery

var listWidth = $("#mytable tr th").map(function() {
  if ($(this).is(":visible")) {
    retu this.style.width;
  }
}).get();
var viewData = {
  thsVisible: []
};
for (var i = 0; i < listWidth.length; i++) {
  var jsonData = {
    width: listWidth[i].slice(0, -2),
    align: 'left'
  };
  viewData.thsVisible.push(jsonData);
}
console.log(viewData);
$('#mytable').fxdHdrCol({
    fixedCols:  0,
    width:     "100%",
    height:    100,
    colModal: viewData
});

Template fiddle

colModal

colModal: [{width: 30, align: 'center'},
           {width: 70, align: 'center'}, 
           {width: 200, align: 'left'}, 
           {width: 100, align: 'center'}, 
           {width: 70, align: 'center'},               
          ]

Template fiddle when have hidden tds

Fiddle I struck with

Getting an error as Uncaught TypeError: Caot read property 'width' of undefined. I need to match the viewData with ColModal.