What is express-validation and how do I use it?

What is express-validation and how do I use it?

Express-validation is a middleware for validating request data in Express.js applications. It helps ensure that incoming data meets specified criteria.

Can you give me an example of how to validate a request body?

Sure! You can use express-validator to check if a field is required. For example:

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 validation fails, you can return a 400 status code along with the error messages, as shown in the example. This informs the client about what went wrong.

Is express-validation compatible with TypeScript?

Yes, express-validation works well with TypeScript. You can define types for your request and validation schemas to ensure type safety.