djvi

Dynamic Json Schema Instance

This package contains json-schema utility for instantiating models based on schema.
This is a part of djv packages aimed to work with json-schema. In future (~1 year) all djv packages will be unified into single package with djv scope.

Usage

For node - package is not minimized

``
npm install djvi
`

For browser

`

`

Use environment

`
var jsonSchema = {"common":{"properties":{"type":{"enum":["common"]}},"required":["type"]}};

var env = new djvi();
env.addSchema('test', jsonSchema);
env.instance('test#/common');
// => { type: 'common' }
`

Concepts

JSON Schema instantiator should generate minimal object, valid to a given schema.

- not required properties will be ommitted
- maximum and minimum will be set up for given number
- primitives types are instantiated with default values
`
null: null
string: ''
boolean: false
number: 0
integer: 0
object: {}
array: []
`
- not recursively changes negative schema to use different types
- anyOf and oneOf are solved with first property instance (for oneOf it should be also checked with single matching only - it is not implemented yet)
- simple dependency instantiates only for required fields
- items keyword instantiates an array with fit objects
- minItems, maxItems instantiates an array with default types
- Each instance is an unique object (Unless unique = false is not used)
`
env.instance('test#/common') !== env.instance('test#/common')
`

Examples

Primitives types with default values

`
{"type":"number","default":100}
// => 100

{"type": "null"}
// => null

{"type": ["integer", "string"]}
// => 0

{"type": "array"}
// => []
`

All of types
`
{ "allOf":[
{"type":"object","properties":{"title":{"type":"string"}},"required":["title"]},
{"type":"object","properties":{"amount":{"type":"number","default":1}},"required":["amount"]}
]}
// => {"title":"","amount":1}
`

Items keywords should instantiate an array with objects
`
{"minItems": 1}
// => [{}]

{"items":[{"type":"integer"},{"type":"string"}]}
// => [0, ""]
`

API

$3

instantiate an object that corresponds to a schema
`
env.instance('test#/common');
// => { type: 'common' }
`

$3

add a schema to djvi environment

`
env.addSchema('test', jsonSchema);
`

$3

removes a schema or the whole structure from djvi environment

`
env.removeSchema('test');
`

$3

resolves name by existing environment

`
env.resolve('test');
// => { name: 'test', schema: {} }, fn: ... }
`

$3

exports the whole structure object from environment or by resolved name

`
env.export();
// => { test: { name: 'test', schema: {}, ... } }
`

$3

imports all found structure objects to internal environment structure

`
env.import(config);
`

$3

returns { types, fieldTypes, fieldValidate, fieldFormat } generators that can be overridden for use cases

`
env.utils();
`

TODO

- add allOf and other cases to not schema
- add oneOf` complex example/generator
- add regexp instantiate (pattern and patternProperties tests)
- add uniqueItems custom logic
- add format generators
- move tests to separated repo/package

Resources

- JSON Schema wiki
- JSON schema specification
- djv
- djvu
- JSON Schema Instantiator tests