Joi-annotate NPM

joi-annotate

joi-annotate is a Node.js module that simplifies the process of creating Joi validators from class annotations. If you're using the Joi library for validation in your Node.js application, and you prefer to define validation rules within your class definitions, this module is for you.

Installation

You can install joi-annotate via npm or yarn:

npm install joi-annotate --save

yarn add joi-annotate

Usage

To use joi-annotate, you need to annotate your class with validation rules using special annotations. Here's a simple example:

import { BooleanF, DateF, NumberF, ObjectF, StringF } from 'joi-annotate'

@ObjectF()
  .unknown(false)
  .min(3)
class User {
  @StringF()
    .min(3)
    .trim()
  a!: string

  @NumberF()
    .multiple(3)
  b!: number

  @BooleanF()
    .truthy('Y')
    .falsy('N')
  d!: boolean

  @DateF()
    .max('12-31-2020')
  f!: Date
}

In this example, we use the BooleanF, DateF, NumberF, ObjectF and StringF annotations to specify the validation rules for the User class properties.

ObjectF annotation is completely optional and only serve if you wish to add validation class wide.

Field ones are mandatory, at least the base one, then all calls are to append to the field validator.

Previous example would be same as

Joi.object({
  a: Joi.string().min(3).trim(),
  b: Joi.number().multiple(3),
  d: Joi.boolean().truthy('Y').falsy('N'),
  f: Joi.date().max('12-31-2020'),
}).unknown(false).min(3)

You can see that Joi.string().min(3).trim() translate to annotation @StringF().min(3).trim() for more simplicity.

You can then create a Joi validator for the User class like this:

import { getSchema } from 'joi-annotate'

const UserValidator = getSchema(User)

Now, you can use UserValidator to validate user objects.

const { error, value } = UserValidator.validate({ email: 'test@example.com', password: 'secret' })
if (error)
  console.error('Validation failed:', error)

else
  console.log('Validation passed:', value)