joi-to-json-schema
The goal is to provide best effort conversion from Joi objects to JSON Schema (draft-04) with the understanding that only some of Joi's schematics can be converted directly. Primarily this module exists to convert Joi schema objects for existing tools which happen to currently consume JSON Schema.
Installation
npm install joi-to-json-schema
Usage
var joi = require('joi'),
convert = require('joi-to-json-schema'),
joiSchema = joi.object({
'name': joi.string().required().regex(/^\w+$/),
'description': joi.string().optional().default('no description provided'),
'a': joi.boolean().required().default(false),
'b': joi.alternatives().when('a', {
is: true,
then: joi.string().default('a is true'),
otherwise: joi.number().default(0)
})
});
convert(joiSchema);
which will produce:
{ type: 'object',
properties:
{ name: { type: 'string', pattern: '^\\w+$' },
description: { default: 'no description provided', type: 'string' },
a: { type: 'boolean', default: false },
b: { oneOf: [ { default: 'a is true', type: 'string' }, { type: 'number', default: 0 } ] } },
additionalProperties: false,
required: [ 'name', 'a' ] }
JSDOC
/**
* Converts the supplied joi validation object into a JSON schema object,
* optionally applying a transformation.
*
* @param {JoiValidation} joi
* @param {TransformFunction} [transformer=null]
* @returns {JSONSchema}
*/
export default function convert(joi,transformer=null) {
// ...
};
/**
* Joi Validation Object
* @typedef {object} JoiValidation
*/
/**
* Transformation Function - applied just before `convert()` returns and called as `function(object):object`
* @typedef {function} TransformFunction
*/
/**
* JSON Schema Object
* @typedef {object} JSONSchema
*/
Notes
Joi's conditional form, i.e. .when('name',{is:cond,then:joi,otherwise:joi})
, is evaluated at runtime
and since, from the perspective of the schema, there is no way of knowing what the condition might resolve to, this
module takes the position that it should provide all possible resolutions in a JSON Schema oneOf:[]
clause.
Testing
All tests cases are first checked against expected results and then validated using Kris Zyp's excellent json-schema
References
- JSON Schema - Draft 4 from json-schema.org
- IETF Draft: JSON Schema: core definitions and terminology - draft-zyp-json-schema-04
- Understanding JSON Schema(pdf)
LICENSE
Copyright 2014, Mozilla Foundation
Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.