.dataset converts String to Float

I have a strange problem with the .dataset functionality. It converts a string into float when assigned to a variable:

var cw_id = $$(this).dataset().cwId;

The following screenshot explains the issue. The cwId value is correctly a string in the dataset, but when assigned to a var it becomes a float.

I’m using FF7 4.4.7

The problem for me is that cwId should stay a string, because the .0 that goes missing is critical.

Just use native dataset as:

var cw_id = $$(this)[0].dataset.cwId;