How do you secure a Node.js application?

Firstly, ensuring data validation and sanitation is critical. In my projects, I've always adhered to the principle of never trusting user input. This involves using robust validation libraries like Joi or express-validator to validate input data against expected formats and sanitize inputs to prevent SQL injection or cross-site scripting (XSS) attacks. For example, when handling user login, I ensure that the email and password fields are strictly checked against predefined formats, and any input that doesn't conform is immediately rejected.

Another cornerstone of my strategy is implementing proper authentication and authorization mechanisms. Utilizing packages like Passport.js for authentication and express-jwt for handling JSON Web Tokens (JWTs) allows for a secure way to manage user sessions. For instance, in a recent project, I...