Headers not showing on IE11

[tenorius]

It seems that even after the last fix on this function, the headers are not showing on IE. Looking into debug, it seems that the actual headers are located in
response.headers.map and the code below just ignores it:

headers: Array.from(res.headers).reduce((res, pair) => {
    res[pair[0]] = pair[1]
    return res
  }, {})

[tenorius]

The solution i found is to check if the property map exists and if so, i get the headers from there using Object.keys. If theres no map property, i use the array.from like above.
It works like a charm now