onResponse returns json even though the header might not be json

[Mathias Nilsson]

We need to look at the actual response to make sure it's not just text. If we make a request to an api endpoint that does not exists it returns a String and will be Uncaught SyntaxError when parsed as json.

[Christian Alfoni]

I believe I fixed that?

    var result = xhr.responseText

    if (xhr.getResponseHeader('content-type').indexOf('application/json') >= 0) {
      result = JSON.parse(xhr.responseText)
    }

:)