let uniqueKeys = [...new Set(fd.keys())];
let normalizeFormData = new FormData();
for(let key of uniqueKeys) {
normalizeFormData.append(key, fd.getAll(key).join('x'));
}
for (let val of normalizeFormData.entries()) {
console.log(val);
}
// 'a': '10x20x30',
// 'b': '60'