What are the best practices for using Joi with TypeScript?

What are the best practices for using Joi with TypeScript?

When using Joi with TypeScript, it's important to define schemas with proper types to leverage TypeScript's type checking.

Can you give me an example of a Joi schema in TypeScript?

Sure! Here's a simple example:

import Joi from 'joi';

const userSchema = Joi.object({
  username: Joi.string().min(3).max(30).required(),
  password: Joi.string().min(8).required(),
});

How do I validate an object against this schema?

You can validate an object using the validate method:

const result = userSchema.validate({ username: 'JohnDoe', password: 'password123' });
if (result.error) {
  console.error(result.error.details);
} else {
  console.log('Validation successful!');
}

What if I want to add custom validation?

You can use the custom method in Joi to add custom validation logic. Here's an example:

const customSchema = Joi.object({
  age: Joi.number().custom((value, helpers) => {
    if (value < 18) {
      return helpers.error('any.invalid');
    }
    return value;
  }),
});