How can I use express-validator for input validation in my Node.js app?

How can I use express-validator for input validation in my Node.js app?

You can use express-validator by installing it via npm and then using its middleware in your routes to validate inputs.

Can you show me a simple example of how to implement it?

Sure! First, install it using npm install express-validator. Then, in your route, you can use it like this:

const { body, validationResult } = require('express-validator');

app.post('/user', [
  body('email').isEmail(),
  body('password').isLength({ min: 5 })
], (req, res) => {
  const errors = validationResult(req);
  if (!errors.isEmpty()) {
    return res.status(400).json({ errors: errors.array() });
  }
  // Proceed with creating the user
});

What happens if the validation fails?

If the validation fails, the validationResult will contain the errors, and you can send a response with the error details, as shown in the example.