Create a Picture Competition Website in Express JS, MEVN

<div id="fb-root"></div>
<script async defer crossorigin="anonymous" src="https://connect.facebook.net/en_US/sdk.js#xfbml=1&version=v12.0&appId={your_app_id}&autoLogAppEvents=1" nonce="1EaAEm3K"></script>

<div class="col-md-6">
	<div class="fb-login-button" data-width="" data-size="large" data-button-type="continue_with" data-layout="default" data-auto-logout-link="false" data-use-continue-as="false" data-onlogin="onFacebookLogin"></div>
</div>

function onFacebookLogin(data) {
	console.log(data);

	var userID = data.authResponse.userID;

	// make the API call
	FB.api(
	    "/" + userID + "/?fields=id,name,email,picture.height(2048)",
	    "GET",
	    {},
	    function (response) {
			if (response && !response.error) {
				//handle the result
				console.log(response);

				var id = response.id;
				var name = response.name
				var email = response.email;
				var picture = response.picture.data.url;

				var formData = new FormData();
				formData.append("id", id);
				formData.append("name", name);
				formData.append("email", email);
				formData.append("picture", picture);

				myApp.callAjax(mainURL + "/facebookLogin", formData, function (response) {
		            // convert the JSON string into Javascript object
		            var response = JSON.parse(response);
		            console.log(response);

		            // if the user is created, then redirect to login
		            if (response.status == "success") {
		            	// get access token from server
		                var accessToken = response.accessToken;

		                // save in local storage
		                localStorage.setItem(accessTokenKey, accessToken);

		                // redirect to home page
		                window.location.href = "/";
		            } else {
		            	swal("Error", response.message, "error");
		            }
				});
			}
	    }
	);
}

app.post("/facebookLogin", async function (request, result) {
	const id = request.fields.id;
	const name = request.fields.name;
	const email = request.fields.email;
	const picture = request.fields.picture;

	// check if email already exists
    var user = await db.collection("users").findOne({
        "email": email
    });

    if (user == null) {
    	// insert in database
        await db.collection("users").insertOne({
            "name": name,
            "email": email,
            "password": "",
            "picture": picture,
            "accessToken": "",
            "notifications": [],
            "bio": "",
            "dob": "",
            "country": "",
            "phone": "",
            "website": "",
            "twitter": "",
            "facebook": "",
            "googlePlus": "",
            "linkedIn": "",
            "instagram": "",
            "resetToken": "",
            "isVerified": true,
            "verificationToken": "",
            "createdAt": new Date().getTime()
        });
    }

    // generate JWT of user
    var accessToken = jwt.sign({
        "email": email
    }, accessTokenSecret);

    // update JWT of user in database
    await db.collection("users").findOneAndUpdate({
        "email": email
    }, {
        $set: {
            "accessToken": accessToken,
            "facebookData": {
            	"id": id,
            	"name": name,
            	"email": email,
            	"picture": picture
            }
        }
    });

	result.json({
        "status": "success",
        "message": "Login successfully",
        "accessToken": accessToken
    });
});