Authorizing the admin in React - node.js

Question

Good day,
i am trying to check if the user is an admin if the user is an admin, he/she will be able to see the content on the page. If not then he/she will be redirected back to the home page. How can i do that? Should i use the backend code for that or can i check it on the frontend.
Route for admin page (this works perfectly fine):
router.get("/adminPanel", isAuth, isAdmin, (req, res) => {
return res.json({
title: "ADMIN PANEL",
});
});
Login page:
const [user, setUser] = useContext(userContext);
const [email, setEmail] = useState("");
const [password, setPassword] = useState("");
const [modal, setModal] = useState(false);
useEffect(() => {
localStorage.setItem("token", JSON.stringify(user));
}, [user]);
//handlesubmit
const handleSubmit = e => {
e.preventDefault();
Axios.post("http://localhost:5000/users/login", {
email,
password,
})
.then(response => {
// localStorage.setItem(
// "token",
// JSON.stringify(response.data.token),
// )((window.location = "/"));
setUser({
token: response.data.token,
isAdmin: response.data.isAdmin,
});
window.location = "/";
// console.log(response.data.token);
// console.log(response.data.isAdmin);
})
.catch(err => {
console.log(err);
});
};
setting the role and the token in the localstorage:
const getLocalStorage = () => {
let token = localStorage.getItem("token");
let admin = localStorage.getItem("admin");
if (token) {
return JSON.parse(localStorage.getItem("token"));
} else if (token && admin) {
return JSON.parse(localStorage.getItem("admin"));
} else {
return "";
}
};
const logoutCallback = () => {
// Axios.post("http://localhost:5000/users/logout");
setUser({});
localStorage.clear("token");
window.location = "/";
};
const [user, setUser] = useState(getLocalStorage());
useEffect(() => {
setUser({ token: localStorage.getItem("token") });
}, []);
console.log(user);
Admin panel:
import React, { useContext, useEffect, useState } from "react";
import Axios from "axios";
import { userContext } from "../../App";
export default function Home() {
const [user] = useContext(userContext);
const [content, setContent] = useState("login plz to display the content");
useEffect(() => {
// if (user.isAdmin) {
// alert("is Admin");
// }
// Axios.get("http://localhost:5000/users/adminPanel").then(response =>
// console.log(user),
// );
async function fetchProtected() {
const result = await (
await fetch("http://localhost:5000/users/adminPanel", {
method: "POST",
headers: {
"Content-Type": "application/json",
authorization: `Bearer ${user.isAdmin}`,
},
})
).json();
if (result.data) setContent(result.data);
}
fetchProtected();
}, [user]);
return <div>{content}</div>;
}