useAuth Hook in React – DEV Community
Authentication and authorization are crucial aspects of web applications. Instead of handling them manually in multiple components, we can create a reusable hook to simplify the logic. In this article, we’ll first implement authentication logic inside a component and then refactor it using a custom useAuth hook.
Authentication logic without a custom hook
Let’s start by creating a React component that manages user authentication manually.
import React, { useState } from "react";
const AuthComponent = () => {
const [user, setUser] = useState(null);
const login = (username) => {
setUser({ name: username, role: "user" });
};
const logout = () => {
setUser(null);
};
return (
<div>
{user ? (
<>
<h2>Welcome, {user.name}!h2>
<button onClick={logout}>Logoutbutton>
>
) : (
<button onClick={() => login("John Doe")}>Loginbutton>
)}
div>
);
};
export default AuthComponent;
Issues with this approach
- Authentication logic is tied to a single component, making it hard to reuse.
- No centralized way to manage user state across the app.
- Authorization checks need to be manually repeated in multiple components.
Creating a Custom useAuth Hook
To make authentication reusable, we’ll create a useAuth hook that manages login, logout, and user state globally.
AuthProvider (Context Provider)
import { useState, createContext } from "react";
export const AuthContext = createContext(null);
export const AuthProvider = ({ children }) => {
const [user, setUser] = useState(() => {
const storedUser = localStorage.getItem("user");
return storedUser ? JSON.parse(storedUser) : null;
});
const login = (username, role) => {
const userData = { name: username, role };
setUser(userData);
localStorage.setItem("user", JSON.stringify(userData));
};
const logout = () => {
setUser(null);
localStorage.removeItem("user");
};
return (
<AuthContext.Provider value={{ user, login, logout }}>
{children}
AuthContext.Provider>
);
};
useAuth Hook
import { useContext } from "react";
import { AuthContext } from "./AuthProvider";
export const useAuth = () => {
const { user, login, logout } = useContext(AuthContext);
const isAuthorized = (requiredRole) => {
return user && user.role === requiredRole;
};
return { user, login, logout, isAuthorized };
};
Advantages
Can be used across multiple components. Provides a centralized authentication state. Eliminates redundant authentication logic.
Using useAuth in a Component
Let’s refactor our authentication component to use the useAuth hook.
import React from "react";
import { useAuth } from "./useAuth";
const AuthComponent = () => {
const { user, login, logout } = useAuth();
return (
<div>
{user ? (
<>
<h2>Welcome, {user.name}!h2>
<button onClick={logout}>Logoutbutton>
>
) : (
<button onClick={() => login("John Doe", "user")}>Loginbutton>
)}
div>
);
};
export default AuthComponent;
Wrapping the Root Component with AuthProvider
To make authentication available across the app, wrap your root component with AuthProvider.
import { StrictMode } from "react";
import { createRoot } from "react-dom/client";
import { AuthProvider } from "./AuthProvider";
import App from "./App";
const rootElement = document.getElementById("root");
const root = createRoot(rootElement);
root.render(
<StrictMode>
<AuthProvider>
<App />
AuthProvider>
StrictMode>
);
Example: Protecting Admin Routes
import React from "react";
import { useAuth } from "./useAuth";
const AdminPanel = () => {
const { user, isAuthorized } = useAuth();
if (!user || !isAuthorized("admin")) {
return <h2>Access Deniedh2>;
}
return <h2>Welcome to the Admin Panelh2>;
};
export default AdminPanel;
Example: Protecting Routes with Higher-Order Component (HOC)
import React from "react";
import { useAuth } from "./useAuth";
import { Navigate } from "react-router-dom";
const ProtectedRoute = ({ children, requiredRole }) => {
const { user, isAuthorized } = useAuth();
if (!user || (requiredRole && !isAuthorized(requiredRole))) {
return <Navigate to="/login" replace />;
}
return children;
};
export default ProtectedRoute;
Advantages
Simplifies role-based access control. Avoids repeating authorization checks. Easily protect routes with a reusable ProtectedRoute component.
