Validate

A JSONSchema validator that uses code generation to be extremely fast

npm install @weo-edu/validate

It passes the entire JSONSchema v4 test suite except for remoteRefs and maxLength/minLength when using unicode surrogate pairs.

Usage

Simply pass a schema to compile it

var validator = require('is-my-json-valid')

var validate = validator({
  required: true,
  type: 'object',
  properties: {
    hello: {
      required: true,
      type: 'string'
    }
  }
})

console.log('should be valid', validate({hello: 'world'}).valid)
console.log('should not be valid', validate({}).valid)

// get the last list of errors by checking validate.errors
// the following will print [{field: 'hello', message: 'is required', code: 'required'}]
console.log(validate.errors)

Custome error messages

Validate adds custom error messages to is-my-json-valid.

var validate = validator({
  type: 'string',
  required: true,
  messages: {
    required: 'this string is required foo'
  }
})


validate()
// {valid: false, errors: [code: 'required', field: '', message: 'this string is required foo']}

Custom formats

is-my-json-valid supports the formats specified in JSON schema v4 (such as date-time). If you want to add your own custom formats pass them as the formats options to the validator

var validate = validator({
  type: 'string',
  required: true,
  format: 'only-a'
}, {
  formats: {
    'only-a': /^a+$/
  }
})

console.log(validate('aa').valid) // true
console.log(validate('ab').valid) // false

External schemas

You can pass in external schemas that you reference using the $ref attribute as the schemas option

var ext = {
  required: true,
  type: 'string'
}

var schema = {
  $ref: '#ext' // references another schema called ext
}

// pass the external schemas as an option
var validate = validate(schema, {schemas: {ext: ext}})

validate('hello').valid // returns true
validate(42).valid // return false

Filtering away additional properties

is-my-json-valid supports filtering away properties not in the schema

var filter = validator.filter({
  required: true,
  type: 'object',
  properties: {
    hello: {type: 'string', required: true}
  },
  additionalProperties: false
})

var doc = {hello: 'world', notInSchema: true}
console.log(filter(doc)) // {hello: 'world'}

Verbose mode outputs the value on errors

is-my-json-valid outputs the value causing an error when verbose is set to true

var validate = validator({
  required: true,
  type: 'object',
  properties: {
    hello: {
      required: true,
      type: 'string'
    }
  }
}, {
  verbose: true
})

validate({hello: 100}).errors
// {field: 'hello', message: 'is the wrong type', value: 100, code: 'type'}

Greedy mode tries to validate as much as possible

By default is-my-json-valid bails on first validation error but when greedy is set to true it tries to validate as much as possible:

var validate = validator({
  type: 'object',
  properties: {
    x: {
      type: 'number'
    }
  },
  required: ['x', 'y']
}, {
  greedy: true
});

validate({x: 'string'}).errors;
// [{field: 'y', message: 'is required', code: 'required'},
//  {field: 'x', message: 'is the wrong type', code: 'type'}]

Performance

is-my-json-valid uses code generation to turn your JSON schema into basic javascript code that is easily optimizeable by v8.

At the time of writing, is-my-json-valid is the fastest validator when running

• json-schema-benchmark
• cosmicreals.com benchmark
• jsck benchmark
• themis benchmark
• z-schema benchmark

If you know any other relevant benchmarks open a PR and I'll add them.

License

MIT