joi-compiler

Build and manage the joi instances for the Fastify framework.

It isolates the joi dependency so its version is not tightly coupled to the Fastify version. This allows the user to decide which version of joi to use in their Fastify based application.

Versions

`joi-compiler`	`joi`	`fastify`
v2.x	v17.x	^5.0
v1.x	v17.x	^4.18

JOI Configuration

The joi's default configuration is:

{
  stripUnknown: true
}

To know all the possible options, please refer to the joi.validate() documentation.

Usage

This module is a Fastify schema compiler, it is used by Fastify to build the schema validator.
You can configure it by setting the Schema Controller, but let's see how to use it directly:

const fastify = require('fastify')
const JoiCompiler = require('joi-compiler')

// Instantiate the compiler
const factory = JoiCompiler()

// Install it to Fastify
const app = fastify({
  schemaController: {
    compilersFactory: {
      buildValidator: factory.buildValidator
    }
  }
})

// Use it!
app.get('/', {
  handler: echo,
  schema: {
    headers: factory.joi.object({
      foo: factory.joi.string().required()
    })
  }
})

Options

The JoiCompiler accepts an optional configuration object:

const factory = JoiCompiler({
  // optionally: provide all the JOI options you need
  prefs: {
    allowUnknown: true
  },

// optionally: an array with custom JOI extensions
  extensions: [
    require('@joi/date')
  ],

  // optionally: if you want to use the async validation. Default: false
  // Note that this option is supported ONLY by Fastify since v4.18.0
  asyncValidation: true
})

When you instantiate the compiler, the returned object has the following properties:

buildValidator: the function to pass to the schemaController option of Fastify
bucket: the object to support fastify.addSchema()
joi: a customized joi instance that contains the installed extensions.

Warning The async joi extensions are supported by Fastify since v4.18.0.

How to use `ref`

The joi module supports the ref feature to link the context configuration.

You can configure the context option by using the fastify.addSchema() method.
Note that, as the Fastify default compiler, this feature is fully encapsulated!

In this case you will need to use a special schema object:

app.addSchema({
  $id: 'x', // the ID you want to use
  $value: 42 // the value you want to store in the context
})

Here is an example:

const factory = JoiCompiler()

const app = fastify({
  schemaController: {
    bucket: factory.bucket,
    compilersFactory: {
      buildValidator: factory.buildValidator
    }
  }
})

app.addSchema({ $id: 'x', $value: 42 })

app.post('/', {
  handler: echo,
  schema: {
    body: Joi.object({
      a: Joi.ref('b.c'),
      b: { c: Joi.any() },
      c: Joi.ref('$x')
    })
  }
})

License

Licensed under MIT.

Eomm/joi-compiler