skeema

JSON schema utilities.

Table of Contents

• Installation
• Documentation
• Code of Conduct
• Contributing
• License

Installation

npm

npm install skeema

yarn

yarn add skeema

Documentation

First if you are unfamiliar with JSON schema you should read up on it first.

Schema helpers

The following methods are meant to help you build a schema, with built in Flow types and runtime validation. If you use Flow for type checking then Flow should catch errors for you, otherwise you'll still get runtime errors when these methods are executed.

Here is an example of how to import all of the following methods:

import {
  allOf,
  anyOf,
  array,
  boolean,
  constant,
  integer,
  nil,
  not,
  number,
  object,
  oneOf,
  string
} from 'skeema'

allOf(schemas, rest)

schemas is an optional argument which should be an array of schemas.

rest is an optional argument which when present should be an object with the following attributes:

Attribute	Required	Type	Description
$comment	No	string	Useful for leaving notes for maintainer of schema
description	No	string	Long explanation about purpose of data described by schema
examples	No	Array<any>	A place to provide examples that validate against schema
title	No	string	Short explanation about purpose of data described by schema

anyOf(schemas, rest)

schemas is an optional argument which should be an array of schemas.

rest is an optional argument which when present should be an object with the following attributes:

Attribute	Required	Type	Description
$comment	No	string	Useful for leaving notes for maintainer of schema
description	No	string	Long explanation about purpose of data described by schema
examples	No	Array<any>	A place to provide examples that validate against schema
title	No	string	Short explanation about purpose of data described by schema

array(schema)

schema is an optional argument which when present should be an object with the following attributes:

Attribute	Required	Type	Description
$comment	No	string	Useful for leaving notes for maintainer of schema
additionalItems	No	boolean or Schema	Whether or not to allow additional items and their schema
contains	No	Schema	Schema one or more items should adhere to
description	No	string	Long explanation about purpose of data described by schema
examples	No	Array<Array<any>>	A place to provide examples that validate against schema
items	No	Schema or Array<Schema>	Schema items should adhere to
maxItems	No	number	Maximum number of items allowed
minItems	No	number	Minimum number of items allowed
title	No	string	Short explanation about purpose of data described by schema
type	No	"boolean"	This is added automatically but can still be included
uniqueItems	No	boolean	Whether or not to ensure each item is unique

boolean(schema)

schema is an optional argument which when present should be an object with the following attributes:

Attribute	Required	Type	Description
$comment	No	string	Useful for leaving notes for maintainer of schema
description	No	string	Long explanation about purpose of data described by schema
examples	No	Array<boolean>	A place to provide examples that validate against schema
title	No	string	Short explanation about purpose of data described by schema
type	No	"boolean"	This is added automatically but can still be included

constant(value, rest)

value is a required argument which can be anything (a string, number, object with deeply nested attributes, etc).

rest is an optional argument which when present should be an object with the following attributes:

Attribute	Required	Type	Description
$comment	No	string	Useful for leaving notes for maintainer of schema
description	No	string	Long explanation about purpose of data described by schema
examples	No	Array<any>	A place to provide examples that validate against schema
title	No	string	Short explanation about purpose of data described by schema

integer(schema)

schema is an optional argument which when present should be an object with the following attributes:

Attribute	Required	Type	Description
$comment	No	string	Useful for leaving notes for maintainer of schema
description	No	string	Long explanation about purpose of data described by schema
examples	No	Array<number>	A place to provide examples that validate against schema
exclusiveMaximum	No	boolean	Whether or not maximum is exclusive
exclusiveMinimum	No	boolean	Whether or not minimum is exclusive
maximum	No	number	The maximum value the integer should be (must be an integer)
minimum	No	number	The minimum value the integer should be (must be an integer)
multipleOf	No	number	What the number should e a multiple of (must be an integer)
title	No	string	Short explanation about purpose of data described by schema
type	No	"integer"	This is added automatically but can still be included

nil(schema)

schema is an optional argument which when present should be an object with the following attributes:

Attribute	Required	Type	Description
$comment	No	string	Useful for leaving notes for maintainer of schema
description	No	string	Long explanation about purpose of data described by schema
examples	No	Array<null>	A place to provide examples that validate against schema
title	No	string	Short explanation about purpose of data described by schema
type	No	"null"	This is added automatically but can still be included

not(schema, rest)

schemas is a required argument which should be a schema.

rest is an optional argument which when present should be an object with the following attributes:

Attribute	Required	Type	Description
$comment	No	string	Useful for leaving notes for maintainer of schema
description	No	string	Long explanation about purpose of data described by schema
examples	No	Array<any>	A place to provide examples that validate against schema
title	No	string	Short explanation about purpose of data described by schema

number(schema)

schema is an optional argument which when present should be an object with the following attributes:

Attribute	Required	Type	Description
$comment	No	string	Useful for leaving notes for maintainer of schema
description	No	string	Long explanation about purpose of data described by schema
examples	No	Array<number>	A place to provide examples that validate against schema
exclusiveMaximum	No	boolean	Whether or not maximum is exclusive
exclusiveMinimum	No	boolean	Whether or not minimum is exclusive
maximum	No	number	The maximum value the number should be
minimum	No	number	The minimum value the number should be
multipleOf	No	number	What the number should e a multiple of
title	No	string	Short explanation about purpose of data described by schema
type	No	"number"	This is added automatically but can still be included

object(schema)

schema is a required argument which when present should be an object with the following attributes:

Attribute	Required	Type	Description
$comment	No	string	Useful for leaving notes for maintainer of schema
additionalProperties	No	boolean or Schema	Whether or not to allow additional properties and their schema
description	No	string	Long explanation about purpose of data described by schema
examples	No	Array<Object>	A place to provide examples that validate against schema
maxProperties	No	number	The maximum number of properties object may contain
minProperties	No	number	The minimum number of properties object may contain
patternProperties	No	Object	Map of regex keys to schemas for validating properties against
properties	Yes	Object	Map of property names to schemas
propertyNames	No	Object	Schema to validate property names against
required	No	Array<string>	List of required properties
title	No	string	Short explanation about purpose of data described by schema
type	No	"object"	This is added automatically but can still be included

oneOf(schemas, rest)

schemas is an optional argument which should be an array of schemas.

rest is an optional argument which when present should be an object with the following attributes:

Attribute	Required	Type	Description
$comment	No	string	Useful for leaving notes for maintainer of schema
description	No	string	Long explanation about purpose of data described by schema
examples	No	Array<any>	A place to provide examples that validate against schema
title	No	string	Short explanation about purpose of data described by schema

string(schema)

schema is an optional argument which when present should be an object with the following attributes:

Attribute	Required	Type	Description
$comment	No	string	Useful for leaving notes for maintainer of schema
description	No	string	Long explanation about purpose of data described by schema
enum	No	Array<string>	List of valid string values
examples	No	Array<string>	A place to provide examples that validate against schema
format	No	string	Format that the string should match
maxLength	No	number	The maximum length the string should be
minLength	No	number	The minimum length the string should be
pattern	No	string	A regular expression pattern the string should match
title	No	string	Short explanation about purpose of data described by schema
type	No	"string"	This is added automatically but can still be included

Validation

In you'd like to validate a JSON schema, whether it was created via skeema's helper methods or is just purely a JSON object, you can use the validateSchema export. The rsult is an object containg both errors and warnings attributes, which are both arrays of objects that contain the attributes message and path.

Example

import {integer, object, string, validateSchema} from 'skeema'

const schema = object({
  properties: {
    bar: string(),
    foo: integer(),
  },
})

const result = validateSchema(schema)

result.errors.forEach(({message, path}) => {
  console.error(`${path}: ${message}`)
})

result.warnings.forEach(({message, path}) => {
  console.warn(`${path}: ${message}`)
})

Code of Conduct

Please see the code of conduct.

Contributing

Please see the contributing guide.

License

MIT