dsl-schema

Write and check schema comilancy with simple DSL

Usage no npm install needed!

<script type="module">
  import dslSchema from 'https://cdn.skypack.dev/dsl-schema';
</script>

README

dsl-schema

So I herd U liek JSON Schema!

dsl-schema provides simple, yet powerful API for building up your JSON Schemas based on examples you provide.

import like from 'dsl-schema'

const mySchema = like({
  foo: 'some string',
  baz: ['yup'],
  // Can be nested for more fine-grained control!
  here: like.Enum('come dat boi', 'I come'),
})

// true
ajv.validate(mySchema, {
  foo: 'bar',
  baz: ['fizz buz'],
  here: 'I come',
})

// false
ajv.validate(mySchema, {
  not: 'valid',
})

Getting started

npm install dsl-schema # OR
yarn add dsl-schema

import like from 'dsl-schema'
const schema = like(1337)

Docs

like

like: (example: any) => Schema
  • For object like example it builds up a Record of its properties
  • For array like example it builds up a Tuple of its elements
  • For primitive example it tries to guess the best schema for it:
    • NULL for null and undefined
    • BOOL for boolean
    • Int for number when it pass Number.isInteger
    • Float for number when it doesn't
    • one of the Constants with fallback to Str for string. Decision is based on very loose RegExps for ISO 8601 date-time, URL, e-mail, IPv4, IPv6 and UUID

like.Str

Str: (opts: string) => Schema

Min and max length can be specified using opts

  • Str('10 > len')
  • Str('3 < length')
  • Str('3 < len <=10')

like.Float

Float: (opts: string) => Schema

Min, max, and multipleOf can be specified using opts

  • Float('1.3 < x')
  • Float('1.3 < x <= 6')
  • Float('n*0.1')
  • Float('1.3 < x <= 6, n*2.6')

like.Int

Int: (opts: string) => Schema

See Float

like.req

req: (s: Schema) => TaggedSchema

Tags schema as required

like.opt

req: (s: Schema) => TaggedSchema

Tags schema as optional

like.Tuple

Tuple: (...items: TaggedSchema[]) => Schema

like.Record

Record: (props: { [key: string]: TaggedSchema }) => Schema

like.Dict

Dict: (opts: string, itemsType: Schema) => Schema
Dict: (itemsType: Schema) => Schema

Size of the dictionary can be specified using opts

  • Dict('size <= 10')
  • Dict('length > 10')
  • Dict('30 > len > 10')

like.List

List: (opts: string, itemsType: Schema) => Schema
List: (itemsType: Schema) => Schema

See Dict. Can also specify uniqueness

  • List('unique')
  • List('uniq, len < 30')

like.Enum

Enum: (...items: (null | boolean | number | string)[]) => Schema

Elements of the items must be unique

like.AllOf

AllOf: (...schemas: Schema[]) => Schema

like.AnyOf

AnyOf: (...schemas: Schema[]) => Schema

like.OneOf

OneOf: (...schemas: Schema[]) => Schema

like.Not

Not: (schema: Schema) => Schema

Constant schemas

  • ANY
  • BOOL
  • NULL
  • DATE
  • TIME
  • DATE_TIME
  • URI
  • URI_REFERENCE
  • URI_TEMPLATE
  • URL
  • EMAIL
  • HOSTNAME
  • IPV4
  • IPV6
  • REGEX
  • UUID