tson-schema

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 tuples
  • objects with lots of required properties
  • big enums

Installing

npm install -S tson-schema

Or

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