Send multiple files from express server to rest api - node.js

Question

I am trying to send multiple files from react to express server and then to microservice. The problem is that my express server is getting crashed whenever I try to upload multiple files.
Here is my express.js side code:
router.post("/upload-files", upload.array("file[]"), async function (req, res) {
let check = new FormData();
// check = req.files;
const file = req.files;
// console.log("DATA------------------------>", file);
// check.append("file", file.buffer, file.originalname);
await axios.post(
constants.URL2 +":9095/upload-files", check,
{
headers: {
...check.getHeaders(),
},
})
.then((res) => {
return res;
})
.then((result) => {
res.send(result.data);
});
});
Here is my React.js side code:
update = () => {
if (this.isValidForm()) {
$(".loader").css({ display: "block" });
$(".overlay").css({ display: "block" });
// const obj = {
// fullName: this.state.fullName,
// };
var formData = new FormData();
const size = this.state.fileData;
for (let i = 0; i < size.length; i++) {
console.log(this.state.fileData[i]);
formData.append("file[]", this.state.fileData[i]);
}
// formData.append("files", this.state.fileData);
const updateRequest = {
method: "POST",
headers: {
// "Content-Type": "application/json",
Authorization:
},
// body: JSON.stringify(obj),
body: formData
};
fetch(URL.BASE_URL + "upload-file", updateRequest)
.then((res) => {
if (res.status == 401) {
this.props.GETLOGGEDINUSER(null);
this.props.history.push("/");
} else {
return res.json();
}
})
.then((res) => {
if (res.statusCode == 0) {
this.props.history.push({
pathname: "/newScreen",
state: { notification: "File uploaded Successfully" },
});
toast.success("File uploaded Successfully");
$(".loader").css({ display: "none" });
$(".overlay").css({ display: "none" });
} else {
toast.error(res.message);
$(".loader").css({ display: "none" });
$(".overlay").css({ display: "none" });
}
});
} else {
}
};
I tried many ways to solve this but none of them works.