JSON Schema Validator

A basic JSON Schema Validator


> DISCLAIMER: This is a basic JSON Schema validator implementation,
it dont implement the full JSON Schema spec, so it's should never used in production.
For a faster and powerful JSON Schema validator, please use AJV

Install

``sh
npm install --save jsonschemav
`

Usage

`javascript
const JsonSchemav = require('jsonschemav')
const jsv = new JsonSchemav()

const schema = {
type: 'object',
properties: {
title: { type: 'string', minLength: 6 },
date: { type: 'string', format: 'date', default: 'now()' }
}
}
const data = { title: 'Hello, World!' }
const validator = jsv.compile(schema)

validator
.then((instance) => instance.validate(datta))
.then((parsedData) => {
// use parsedData instead data
console.log(parsedData)
// { title: 'Hello, World!',
// date: '2017-06-12T18:49:14.739Z' }
})

validator
.then((instance) => instance.validate('Hello'))
.catch((err) => {
console.error(err.errors)
// [ { keyword: 'minLength',
// size: 5,
// minLength: 6,
// message: 'not enough characters. must be greater than, or equal to, 6' } ]
})

validator
.then((instance) => instance.validate(true))
.catch((err) => {
console.error(err.errors)
// [ { keyword: 'type', message: 'invalid type input' } ]
})
`

$3

`javascript
const axios = require('axios')
const JsonSchemav = require('jsonschemav')

const jsv = new JsonSchemav()
const schema = { type: 'string', isTwitterAccount: true }
const endpoint = 'https://twitter.com/users/username_available'
const validationFn = (value, data) => {
// value is the keyword value
// data.value is the user data

if (value === true) {
return axios.get(${endpoint}?username=${data.value})
.then((response) => {
if (response.data.valid) {
const message = The username '${data.value}' does not exists
const err = new Error()

err.props = { message }

throw err
}

return Promise.resolve(data.value)
})
}

return true
}

jsv.addKeyword('string', 'isTwitterAccount', validationFn)

const validator = jsv.compile(schema)

validator
.then((instance) => instance.validate('nonexistingac'))
.catch((err) => {
console.error(err.errors)
// [ { message: 'The username \'nonexistingac\' does not exists',
// keyword: 'isTwitterAccount' } ]

})

validator
.then((instance) => instance.validate('demsking'))
.then((parsedData) => {
console.log('success')
})
`

JSV API

#### Table of Contents

- validateSchema()
- compile()
- addCompileStep()
- addAlias()
- addType()
- removeType()
- addKeyword()
- removeKeyword()

$3

Validate a schema. Throws an error for invalid schema

#### Parameters

- schema object Schema to validate

#### Examples

`javascript
const jsv = new JsonSchemav()
const schema = { type: 'string' }

try {
jsv.validateSchema(schema)
} catch (err) {
console.error(err)
}
`

$3

Compile a schema

#### Parameters

- schema object Schema to compile

#### Examples

`javascript
const jsv = new JsonSchemav()
const schema = {
type: 'object',
properties: {
title: { type: 'string' },
date: { type: 'string', format: 'date', default: 'now()' }
}
}
const data = { title: 'Hello, World!' }

jsv.compile(schema)
.then((instance) => instance.validate(data))
.then((parsedData) => {
// use parsedData instead data
console.log(parsedData)
// { title: 'Hello, World!',
// date: '2017-06-12T18:49:14.739Z' }
})
.catch((err) => {
console.error(err.errors) // a list of parsing error
})
`

Returns Promise Returns the validation interface on success and an error otherwise

$3

Add a compile step function to a type

#### Parameters

- type string The name of the type
- compileStepFn function A compile function

$3

Add an alias for a type

#### Parameters

- type string The name of a defined type
- name string The alias name

#### Examples

`javascript
const jsv = new JsonSchemav()
const schema = { type: 'int' }
const data = 123

jsv.addAlias('integer', 'int')
jsv.compile(schema)
.then((instance) => instance.validate(data))
.then((parsedData) => {
// use parsedData instead data
console.log(parsedData) // 123
})
.catch((err) => {
// err.errors is a list of parsing error
})
`

$3

Add a new type to the instance

#### Parameters

- name string The name of the new type
- validateFn function? A validate function for the new type

#### Examples

`javascript
const jsv = new JsonSchemav()
const validateFn = (data) => {
return Number.isInteger(data.value) && /^[01]+$/.test(data.value.toString())
}

jsv.addType('binary', validateFn)

const schema = { type: 'binary' }
const data = 1111011
const instance = jsv.compile(schema)

jsv.compile(schema)
.then((instance) => instance.validate(data))
.then((parsedData) => {
// use parsedData instead data
console.log(parsedData) // 1111011
})
`

$3

Remove a type from the instance

#### Parameters

- name string The nema of the type

#### Examples

`javascript
const schema = { type: 'string' }
const jsv = new JsonSchemav()

jsv.removeType('string')

try {
jsv.validateSchema(schema)
} catch (err) {
console.error(err) // Error: Unknown type 'string'
}
`

$3

Add a new keyword to a type

#### Parameters

- type string The name of the type
- name string The name of the new keyword
- validateFn function A validate function for the new keyword

#### Examples

`javascript
const jsv = new JsonSchemav()
const validateFn = function (value, data) {
// value is the keyword value
// data.value is the user data
// the function must returns:
// - true: for a success validation
// - false: for a faillure validate
// - an object { message, errors }
// - a Promise for async validation

return new Promise((resolve, reject) => {
//...
})
}

jsv.addKeyword('string', 'provider', validateFn)

// and then
const schema = {
type: 'object',
properties: {
account: { type: 'string', provider: 'twitter' }
}
}
`

$3

Remove a keyword from a type

#### Parameters

- type string The name of the type
- name string The name of the keyword

#### Examples

`javascript
const jsv = new JsonSchemav()

jsv.removeKeyword('string', 'minLength')

const schema = { type: 'string', minLength: 5 }
const instance = jsv.compile(schema)
const data = 'abc'

jsv.compile(schema)
.then((instance) => instance.validate(data))
.then((parsedData) => {
// success
})
``

License

Under the MIT license. See LICENSE file for more details.