How do you perform authentication in Node.js?

Authentication in Node.js involves verifying the identity of users before granting access to protected resources. There are various authentication methods and strategies available, but the most common ones include:

• Session-based Authentication: Session-based authentication involves using sessions to track the authenticated state of users. When a user logs in, a session is created and stored on the server, and a session identifier (usually stored in a cookie) is sent to the client. Subsequent requests include the session identifier, allowing the server to verify the user’s identity.
• Token-based Authentication: Token-based authentication involves issuing tokens (e.g., JSON Web Tokens or JWTs) to authenticated users. When a user logs in, a token containing user information and a signature is generated and sent to the client. The client includes the token in subsequent requests, and the server verifies the token’s authenticity and extracts user information from it.
• OAuth and OpenID Connect: OAuth and OpenID Connect are authentication protocols used for delegated authorization and single sign-on (SSO) scenarios. OAuth allows third-party applications to access resources on behalf of users, while OpenID Connect builds on top of OAuth to provide identity authentication and federation.

To implement authentication in Node.js, you can use authentication middleware libraries such as Passport.js, which provides a flexible and extensible framework for implementing various authentication strategies, including local authentication (username and password), OAuth, JWT, and more. Additionally, you can use middleware for session management, such as Express Session, to handle session-based authentication.