How do I validate nested objects in Express?

How do I validate nested objects in Express?

You can use libraries like Joi or express-validator to validate nested objects in Express. Would you like an example?

Yes, please provide an example using Joi.

Sure! Here's a simple example:

const Joi = require('joi');

const schema = Joi.object({
  user: Joi.object({
    name: Joi.string().required(),
    age: Joi.number().integer().min(0).required()
  }).required()
});

app.post('/api/users', (req, res) => {
  const { error } = schema.validate(req.body);
  if (error) return res.status(400).send(error.details[0].message);
  res.send('User is valid!');
});

This will validate a nested user object.

What if I want to add more fields to the nested object?

You can simply extend the Joi schema. For example, if you want to add an email field:

const schema = Joi.object({
  user: Joi.object({
    name: Joi.string().required(),
    age: Joi.number().integer().min(0).required(),
    email: Joi.string().email().required()
  }).required()
});