Element.prototype.dataset polyfill enumerability

[jlewis-edr]

When grabbing a DOM element using document.getElementById and calling dataset, the returned object is not enumerable. The polyfill is setting the properties enumerable value to the elements enumerable value, but for DOM elements it is undefined. This results in a for-in loop not working. Is there a workaround or can the enumerable value for the properties just be set to true?

This occurs in IE 9 and 10.