AJAX request fails when sending FormData() including empty file input in Safari 10.13.4

Question

I am running a Symfony 2.8 based web app which sends some form data back to a controller using Ajax.

So far everything worked fine, but since the latest macOS update

Answer 1

I used Andrei's suggestion, which worked for safari, but broke IE.

The only solution I could find that would work in both browsers was to use eval().

Since this appears to be a bug only affecting safari 11 I also added a check on browser version.

if(dataObj instanceof FormData && navigator.userAgent.match(/version\/11((\.[0-9]*)*)? .*safari/i)) {
    try {
        eval('for (var pair of dataObj.entries()) {\
            if (pair[1] instanceof File && pair[1].name === \'\' && pair[1].size === 0) {\
                dataObj.delete(pair[0]);\
            }\
        }');
    } catch(e) {}
}