mjwwit / tson-schema Goto Github PK

A TypeScript API to create JSON-Schemas and TypeScript types

TypeScript 99.42% JavaScript 0.58%

tson-schema's Introduction

tson-schema

This project aims to bring you an easy way to create json-schemas and TypeScript types using a single API. This API is kept as close as possible to json-schema so you don't have to worry about learning yet another API. Support for new json-schema versions and new TypeScript versions is added on a best effort basis.

This is a work in progress! Known missing json-schema features include:

array.additionalItems
object.additionalProperties
$ref
JSON-Schema conditional schemas (if/else)
Limited TypeScript support for:
- big enum schemas
- big allOf schemas

Installing

npm install -S tson-schema

yarn add tson-schema

Usage

import * as t from 'tson-schema'

/**
 * Array
 */
const numberArraySchema = t.array({
  items: t.number({
    minimum: 1
  }),
  minItems: 2,
  uniqueItems: true
})

numberArraySchema.getSchema() // { type: 'array', items: { type: 'number', minimum: 1 }, minItems: 2, uniqueItems: true }
numberArraySchema.type        // number[]

/**
 * Object
 */
const objectSchema = t.object({
  properties: {
    req: t.string(),
    opt: t.tuple({
      items: [t.integer()]
    })
  },
  required: ['req']
})

objectSchema.getSchema() // { type: 'object', properties: { req: { type: 'string' }, opt: { type: 'array', items: [{ type: 'integer' }] } }, required: ['req'] }
objectSchema.type        // { req: 'string', opt?: [number] }

/**
 * Enum
 */
const enumSchema = t.enum(['A', 2, 'C', 4])

enumSchema.getSchema() // { enum: ['A', 2, 'C', 4] }
enumSchema.type        // 'A' | 2 | 'C' | 4

/**
 * anyOf
 */
const anyOfSchema = t.anyOf([
  s.const('A'),
  s.integer()
])

enumSchema.getSchema() // { anyOf: [{ const: 'A' }, { type: 'integer' }] }
enumSchema.type        // 'A' | number

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tson-schema's Issues

Improve method names of API

Currently, the library uses capitalized names close to or even the same as JSON-Schema type values. This should be brought closer to the JSON-Schema API.

Make object properties and required optional

The library currently incorrectly marks the properties and required properties of the object type as required, while they are optional in json-schema. Figure out a way to make them optional while retaining the current functionality.

Add json-schema annotation metadata properties

JSON-Schema defines a set of generic keywords used to give meaning and or contextual information to users of the schema. This library shouldn't do anything functional with those properties, but they should be allowed properties for all types.

The properties: are title, description, default, examples, and $comment

Implement support for enums

JSON-Schema supports the use of enums to allow a limited number of values to pass schema validation and TypeScript supports a very similar feature. Implement enum in a way that stays as close as possible to the JSON-Schema API.

Add support for object additionalProperties

The json-schema object type allows you to restrict the type of additional properties in an object, as documented here. TypeScript allows a similar feature (object index signatures). This should be implemented as close as possible to the json-schema API.