How can I implement nested validation with express-validator?

How can I implement nested validation with express-validator?

You can use the check and body methods to validate nested objects. For example, use body('user.name').isString() to validate a nested property.

Can you show me a code example?

Sure! Here's a simple example:

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

app.post('/user', [
  body('user.name').isString().notEmpty(),
  body('user.age').isInt({ min: 0 })
], (req, res) => {
  // Handle request
});

What if I want to validate an array of nested objects?

You can use body('users.*.name').isString() to validate each object in the array. The * acts as a wildcard.

Thanks! Is there a way to customize error messages?

Yes! You can use the withMessage method to customize error messages, like this:

body('user.name').isString().withMessage('Name must be a string!')