You can try to run the following code to detect folders in Safari −
Array.prototype.forEach.call(e.dataTransfer.files, function (file) {
var r = new FileReader();
r.onload = function (event) {
addFile(file);
};
r.onerror = function (event) {
alert("Uploading folders isn't supported in Safari browser!");
}
r.readAsDataURL(file);
});