How can I automate parameter validation in my application?

How can I automate parameter validation in my application?

You can automate parameter validation by using libraries or frameworks that support validation rules, like Joi or Yup.

Can you give me an example of how to use Joi for this?

Sure! Here's a simple example:

const Joi = require('joi');

const schema = Joi.object({
  username: Joi.string().alphanum().min(3).max(30).required(),
  password: Joi.string().pattern(new RegExp('^[a-zA-Z0-9]{3,30}$')).required(),
});

const { error, value } = schema.validate({ username: 'abc', password: '123' });
if (error) {
  console.log(error.details);
} else {
  console.log('Validation passed:', value);
}

What if the validation fails?

If validation fails, Joi will return an error object containing details about what went wrong, which you can use to inform the user.

Are there other libraries I can use for parameter validation?

Yes, other popular libraries include Yup, Validator.js, and express-validator, each with its own features and use cases.