$ npm install @sinclair/typebox --save
import { Static, Type } from 'https://deno.land/x/typebox/src/typebox.ts'
import { Static, Type } from '@sinclair/typebox'
const T = Type.String() // const T = { "type": "string" }
type T = Static<typeof T> // type T = string
TypeBox is a library that builds in-memory JSON Schema objects that can be statically resolved to TypeScript types. The schemas produced by this library are designed to match the static type checking rules of the TypeScript compiler. TypeBox allows one to create a unified type that can be statically checked by the TypeScript compiler and runtime asserted using standard JSON Schema validation.
TypeBox can be used as a simple tool to build up complex schemas or integrated into RPC or REST services to help validate JSON data received over the wire. TypeBox does not provide any JSON schema validation. Please use libraries such as AJV to validate schemas built with this library.
Requires TypeScript 4.3.5 and above.
License MIT
- Install
- Overview
- Example
- Types
- Modifiers
- Options
- Generic Types
- Reference Types
- Recursive Types
- Extended Types
- Strict
- Validation
- OpenAPI
The following demonstrates TypeBox's general usage.
import { Static, Type } from '@sinclair/typebox'
//--------------------------------------------------------------------------------------------
//
// Let's say you have the following type ...
//
//--------------------------------------------------------------------------------------------
type T = {
id: string,
name: string,
timestamp: number
}
//--------------------------------------------------------------------------------------------
//
// ... you can express this type in the following way.
//
//--------------------------------------------------------------------------------------------
const T = Type.Object({ // const T = {
id: Type.String(), // type: 'object',
name: Type.String(), // properties: {
timestamp: Type.Integer() // id: {
}) // type: 'string'
// },
// name: {
// type: 'string'
// },
// timestamp: {
// type: 'integer'
// }
// },
// required: [
// "id",
// "name",
// "timestamp"
// ]
// }
//--------------------------------------------------------------------------------------------
//
// ... then infer back to the original static type this way.
//
//--------------------------------------------------------------------------------------------
type T = Static<typeof T> // type T = {
// id: string,
// name: string,
// timestamp: number
// }
//--------------------------------------------------------------------------------------------
//
// ... then use the type both as JSON schema and as a TypeScript type.
//
//--------------------------------------------------------------------------------------------
function receive(value: T) { // ... as a Type
if(JSON.validate(T, value)) { // ... as a Schema
// ok...
}
}
The following table outlines the TypeBox mappings between TypeScript and JSON schema.
┌────────────────────────────────┬─────────────────────────────┬────────────────────────────────┐
│ TypeBox │ TypeScript │ JSON Schema │
│ │ │ │
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
│ const T = Type.Any() │ type T = any │ const T = { } │
│ │ │ │
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
│ const T = Type.Unknown() │ type T = unknown │ const T = { } │
│ │ │ │
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
│ const T = Type.String() │ type T = string │ const T = { │
│ │ │ type: 'string' │
│ │ │ } │
│ │ │ │
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
│ const T = Type.Number() │ type T = number │ const T = { │
│ │ │ type: 'number' │
│ │ │ } │
│ │ │ │
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
│ const T = Type.Integer() │ type T = number │ const T = { │
│ │ │ type: 'integer' │
│ │ │ } │
│ │ │ │
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
│ const T = Type.Boolean() │ type T = boolean │ const T = { │
│ │ │ type: 'boolean' │
│ │ │ } │
│ │ │ │
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
│ const T = Type.Null() │ type T = null │ const T = { │
│ │ │ type: 'null' │
│ │ │ } │
│ │ │ │
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
│ const T = Type.RegEx(/foo/) │ type T = string │ const T = { │
│ │ │ type: 'string', │
│ │ │ pattern: 'foo' │
│ │ │ } │
│ │ │ │
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
│ const T = Type.Literal(42) │ type T = 42 │ const T = { │
│ │ │ const: 42 │
│ │ │ type: 'number' │
│ │ │ } │
│ │ │ │
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
│ const T = Type.Array( │ type T = number[] │ const T = { │
│ Type.Number() │ │ type: 'array', │
│ ) │ │ items: { │
│ │ │ type: 'number' │
│ │ │ } │
│ │ │ } │
│ │ │ │
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
│ const T = Type.Object({ │ type T = { │ const T = { │
│ x: Type.Number(), │ x: number, │ type: 'object', │
│ y: Type.Number() │ y: number │ properties: { │
│ }) │ } │ x: { │
│ │ │ type: 'number' │
│ │ │ }, │
│ │ │ y: { │
│ │ │ type: 'number' │
│ │ │ } │
│ │ │ }, │
│ │ │ required: ['x', 'y'] │
│ │ │ } │
│ │ │ │
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
│ const T = Type.Tuple([ │ type T = [number, number] │ const T = { │
│ Type.Number(), │ │ type: 'array', │
│ Type.Number() │ │ items: [ │
│ ]) │ │ { │
│ │ │ type: 'number' │
│ │ │ }, { │
│ │ │ type: 'number' │
│ │ │ } │
│ │ │ ], │
│ │ │ additionalItems: false, │
│ │ │ minItems: 2, │
│ │ │ maxItems: 2, │
│ │ │ } │
│ │ │ │
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
│ enum Foo { │ enum Foo { │ const T = { │
│ A, │ A, │ anyOf: [{ │
│ B │ B │ type: 'number', │
│ } │ } │ const: 0 │
│ │ │ }, { │
│ const T = Type.Enum(Foo) │ type T = Foo │ type: 'number', │
│ │ │ const: 1 │
│ │ │ }] │
│ │ │ } │
│ │ │ │
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
│ const T = Type.KeyOf( │ type T = keyof { │ const T = { │
│ Type.Object({ │ x: number, │ enum: ['x', 'y'], │
│ x: Type.Number(), │ y: number │ type: 'string' │
│ y: Type.Number() │ } │ } │
│ }) │ │ │
│ ) │ │ │
│ │ │ │
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
│ const T = Type.Union([ │ type T = string | number │ const T = { │
│ Type.String(), │ │ anyOf: [{ │
│ Type.Number() │ │ type: 'string' │
│ ]) │ │ }, { │
│ │ │ type: 'number' │
│ │ │ }] │
│ │ │ } │
│ │ │ │
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
│ const T = Type.Intersect([ │ type T = { │ const T = { │
│ Type.Object({ │ x: number │ allOf: [{ │
│ x: Type.Number() │ } & { │ type: 'object', │
│ }), │ y: number │ properties: { │
│ Type.Object({ │ } │ a: { │
│ y: Type.Number() │ │ type: 'number' │
│ }) │ │ } │
│ }) │ │ }, │
│ │ │ required: ['a'] │
│ │ │ }, { │
│ │ │ type: 'object', │
│ │ │ properties: { │
│ │ │ b: { │
│ │ │ type: 'number' │
│ │ │ } │
│ │ │ }, │
│ │ │ required: ['b'] │
│ │ │ }] │
│ │ │ } │
│ │ │ │
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
│ const T = Type.Record( │ type T = { │ const T = { │
│ Type.String(), │ [key: string]: number │ type: 'object', │
│ Type.Number() │ } │ patternProperties: { │
│ ) │ │ '^.*$': { │
│ │ │ type: 'number' │
│ │ │ } │
│ │ │ } │
│ │ │ } │
│ │ │ │
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
│ const T = Type.Partial( │ type T = Partial<{ │ const T = { │
│ Type.Object({ │ x: number, │ type: 'object', │
│ x: Type.Number(), │ y: number │ properties: { │
│ y: Type.Number() | }> │ x: { │
│ }) │ │ type: 'number' │
│ ) │ │ }, │
│ │ │ y: { │
│ │ │ type: 'number' │
│ │ │ } │
│ │ │ } │
│ │ │ } │
│ │ │ │
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
│ const T = Type.Required( │ type T = Required<{ │ const T = { │
│ Type.Object({ │ x?: number, │ type: 'object', │
│ x: Type.Optional( │ y?: number │ properties: { │
│ Type.Number() | }> │ x: { │
│ ), │ │ type: 'number' │
│ y: Type.Optional( │ │ }, │
│ Type.Number() │ │ y: { │
│ ) │ │ type: 'number' │
│ }) │ │ } │
│ ) │ │ } │
│ │ │ required: ['x', 'y'] │
│ │ │ } │
│ │ │ │
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
│ const T = Type.Pick( │ type T = Pick<{ │ const T = { │
│ Type.Object({ │ x: number, │ type: 'object', │
│ x: Type.Number(), │ y: number │ properties: { │
│ y: Type.Number(), | }, 'x'> │ x: { │
│ }), ['x'] │ │ type: 'number' │
│ ) │ │ } │
│ │ │ }, │
│ │ │ required: ['x'] │
│ │ │ } │
│ │ │ │
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
│ const T = Type.Omit( │ type T = Omit<{ │ const T = { │
│ Type.Object({ │ x: number, │ type: 'object', │
│ x: Type.Number(), │ y: number │ properties: { │
│ y: Type.Number(), | }, 'x'> │ y: { │
│ }), ['x'] │ │ type: 'number' │
│ ) │ │ } │
│ │ │ }, │
│ │ │ required: ['y'] │
│ │ │ } │
│ │ │ │
└────────────────────────────────┴─────────────────────────────┴────────────────────────────────┘
TypeBox provides modifiers that can be applied to an objects properties. This allows for optional
and readonly
to be applied to that property. The following table illustates how they map between TypeScript and JSON Schema.
┌────────────────────────────────┬─────────────────────────────┬────────────────────────────────┐
│ TypeBox │ TypeScript │ JSON Schema │
│ │ │ │
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
│ const T = Type.Object({ │ type T = { │ const T = { │
│ name: Type.Optional( │ name?: string, │ type: 'object', │
│ Type.String(), │ } │ properties: { │
│ ) │ │ name: { │
│ }) │ │ type: 'string' │
│ │ │ } │
│ │ │ } │
│ │ │ } │
│ │ │ │
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
│ const T = Type.Object({ │ type T = { │ const T = { │
│ name: Type.Readonly( │ readonly name: string, │ type: 'object', │
│ Type.String(), │ } │ properties: { │
│ ) │ │ name: { │
│ }) │ │ type: 'string' │
│ │ │ } │
│ │ │ }, │
│ │ │ required: ['name'] │
│ │ │ } │
│ │ │ │
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
│ const T = Type.Object({ │ type T = { │ const T = { │
│ name: Type.ReadonlyOptional( │ readonly name?: string, │ type: 'object', │
│ Type.String(), │ } │ properties: { │
│ ) │ │ name: { │
│ }) │ │ type: 'string' │
│ │ │ } │
│ │ │ } │
│ │ │ } │
│ │ │ │
└────────────────────────────────┴─────────────────────────────┴────────────────────────────────┘
You can pass additional JSON schema options on the last argument of any given type. The following are some examples.
// string must be an email
const T = Type.String({ format: 'email' })
// number must be a multiple of 2
const T = Type.Number({ multipleOf: 2 })
// array must have at least 5 integer values
const T = Type.Array(Type.Integer(), { minItems: 5 })
Generic types can be created using functions. The following creates a generic Nullable<T>
type.
import { Type, Static, TSchema } from '@sinclair/typebox'
// type Nullable<T> = T | null
const Nullable = <T extends TSchema>(type: T) => Type.Union([type, Type.Null()])
const T = Nullable(Type.String()) // const T = {
// "anyOf": [{
// type: 'string'
// }, {
// type: 'null'
// }]
// }
type T = Static<typeof T> // type T = string | null
const U = Nullable(Type.Number()) // const U = {
// "anyOf": [{
// type: 'number'
// }, {
// type: 'null'
// }]
// }
type U = Static<typeof U> // type U = number | null
Types can be referenced with Type.Ref(...)
. To reference a type, the target type must specify an $id
.
const T = Type.String({ $id: 'T' }) // const T = {
// $id: 'T',
// type: 'string'
// }
const R = Type.Ref(T) // const R = {
// $ref: 'T'
// }
It can be helpful to organize shared referenced types under a common namespace. The Type.Box(...)
function can be used to create a shared definition container for related types. The following creates a Math3D
container and a Vertex
structure that references types in the container.
const Math3D = Type.Box({ // const Math3D = {
Vector4: Type.Object({ // $id: 'Math3D',
x: Type.Number(), // definitions: {
y: Type.Number(), // Vector4: {
z: Type.Number(), // type: 'object',
w: Type.Number() // properties: {
}), // x: { type: 'number' },
Vector3: Type.Object({ // y: { type: 'number' },
x: Type.Number(), // z: { type: 'number' },
y: Type.Number(), // w: { type: 'number' }
z: Type.Number() // },
}), // required: ['x', 'y', 'z', 'w']
Vector2: Type.Object({ // },
x: Type.Number(), // Vector3: {
y: Type.Number() // type: 'object',
}) // properties: {
}, { $id: 'Math3D' }) // x: { 'type': 'number' },
// y: { 'type': 'number' },
// z: { 'type': 'number' }
// },
// required: ['x', 'y', 'z']
// },
// Vector2: {
// type: 'object',
// properties: {
// x: { 'type': 'number' },
// y: { 'type': 'number' },
// },
// required: ['x', 'y']
// }
// }
// }
const Vertex = Type.Object({ // const Vertex = {
position: Type.Ref(Math3D, 'Vector4'), // type: 'object',
normal: Type.Ref(Math3D, 'Vector3'), // properties: {
uv: Type.Ref(Math3D, 'Vector2') // position: { $ref: 'Math3D#/definitions/Vector4' },
}) // normal: { $ref: 'Math3D#/definitions/Vector3' },
// uv: { $ref: 'Math3D#/definitions/Vector2' }
// },
// required: ['position', 'normal', 'uv']
// }
Recursive types can be created with the Type.Rec(...)
function. The following creates a Node
type that contains an array of inner Nodes. Note that due to current restrictions on TypeScript inference, it is not possible for TypeBox to statically infer for recursive types. TypeBox will infer the inner recursive type as any
.
const Node = Type.Rec(Self => Type.Object({ // const Node = {
id: Type.String(), // $id: 'Node',
nodes: Type.Array(Self), // $ref: 'Node#/definitions/self',
}), { $id: 'Node' }) // definitions: {
// self: {
// type: 'object',
// properties: {
// id: {
// type: 'string'
// },
// nodes: {
// type: 'array',
// items: {
// $ref: 'Node#/definitions/self'
// }
// }
// }
// }
// }
type Node = Static<typeof Node> // type Node = {
// id: string
// nodes: any[]
//
function visit(node: Node) {
for(const inner of node.nodes) {
visit(inner as Node) // Assert inner as Node
}
}
In addition to JSON schema types, TypeBox provides several extended types that allow for function
and constructor
types to be composed. These additional types are not valid JSON Schema and will not validate using typical JSON Schema validation. However, these types can be used to frame JSON schema and describe callable interfaces that may receive JSON validated data. These types are as follows.
┌────────────────────────────────┬─────────────────────────────┬────────────────────────────────┐
│ TypeBox │ TypeScript │ Extended Schema │
│ │ │ │
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
│ const T = Type.Constructor([ │ type T = new ( │ const T = { │
│ Type.String(), │ arg0: string, │ type: 'constructor' │
│ Type.Number(), │ arg1: number │ arguments: [{ │
│ ], Type.Boolean()) │ ) => boolean │ type: 'string' │
│ │ │ }, { │
│ │ │ type: 'number' │
│ │ │ }], │
│ │ │ returns: { │
│ │ │ type: 'boolean' │
│ │ │ } │
│ │ │ } │
│ │ │ │
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
│ const T = Type.Function([ │ type T = ( │ const T = { │
| Type.String(), │ arg0: string, │ type : 'function', │
│ Type.Number(), │ arg1: number │ arguments: [{ │
│ ], Type.Boolean()) │ ) => boolean │ type: 'string' │
│ │ │ }, { │
│ │ │ type: 'number' │
│ │ │ }], │
│ │ │ returns: { │
│ │ │ type: 'boolean' │
│ │ │ } │
│ │ │ } │
│ │ │ │
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
│ const T = Type.Promise( │ type T = Promise<string> │ const T = { │
│ Type.String() │ │ type: 'promise', │
│ ) │ │ item: { │
│ │ │ type: 'string' │
│ │ │ } │
│ │ │ } │
│ │ │ │
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
│ const T = Type.Undefined() │ type T = undefined │ const T = { │
│ │ │ type: 'undefined' │
│ │ │ } │
│ │ │ │
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
│ const T = Type.Void() │ type T = void │ const T = { │
│ │ │ type: 'void' │
│ │ │ } │
│ │ │ │
└────────────────────────────────┴─────────────────────────────┴────────────────────────────────┘
TypeBox includes the properties kind
and modifier
on each underlying schema. These properties are used to help TypeBox statically resolve the schemas to the appropriate TypeScript type as well as apply the appropriate modifiers to an objects properties (such as optional). These properties are not strictly valid JSON schema so in some cases it may be desirable to omit them. TypeBox provides a Type.Strict()
function that will omit these properties if nessasary.
const T = Type.Object({ // const T = {
name: Type.Optional(Type.String()) // kind: Symbol(ObjectKind),
}) // type: 'object',
// properties: {
// name: {
// kind: Symbol(StringKind),
// type: 'string',
// modifier: Symbol(OptionalModifier)
// }
// }
// }
const U = Type.Strict(T) // const U = {
// type: 'object',
// properties: {
// name: {
// type: 'string'
// }
// }
// }
TypeBox does not provide JSON schema validation functionality, so users will need to select an appropriate JSON Schema validator for their language or framework. TypeBox targets JSON Schema draft 2019-09
so any validator capable of draft 2019-09
should be fine. A good library to use for validation in JavaScript environments is AJV. The following example shows setting up AJV 7 to work with TypeBox.
$ npm install ajv ajv-formats --save
//--------------------------------------------------------------------------------------------
//
// Import the 2019 compliant validator from AJV
//
//--------------------------------------------------------------------------------------------
import { Type } from '@sinclair/typebox'
import addFormats from 'ajv-formats'
import Ajv from 'ajv/dist/2019'
//--------------------------------------------------------------------------------------------
//
// Setup AJV validator with the following options and formats
//
//--------------------------------------------------------------------------------------------
const ajv = addFormats(new Ajv({}), [
'date-time',
'time',
'date',
'email',
'hostname',
'ipv4',
'ipv6',
'uri',
'uri-reference',
'uuid',
'uri-template',
'json-pointer',
'relative-json-pointer',
'regex'
]).addKeyword('kind')
.addKeyword('modifier')
//--------------------------------------------------------------------------------------------
//
// Create a TypeBox type
//
//--------------------------------------------------------------------------------------------
const User = Type.Object({
userId: Type.String({ format: 'uuid' }),
email: Type.String({ format: 'email' }),
online: Type.Boolean(),
}, { additionalProperties: false })
//--------------------------------------------------------------------------------------------
//
// Validate Data
//
//--------------------------------------------------------------------------------------------
const ok = ajv.validate(User, {
userId: '68b4b1d8-0db6-468d-b551-02069a692044',
email: '[email protected]',
online: true
}) // -> ok
Referenced types can be added to AJV with the ajv.addSchema(...)
function. The following moves the userId
and email
property types into a Type.Box(...)
and registers the box with AJV.
//--------------------------------------------------------------------------------------------
//
// Shared Types
//
//--------------------------------------------------------------------------------------------
const Shared = Type.Box({
UserId: Type.String({ format: 'uuid' }),
Email: Type.String({ format: 'email' })
}, { $id: 'Shared' })
//--------------------------------------------------------------------------------------------
//
// Setup Validator and Register Shared Types
//
//--------------------------------------------------------------------------------------------
const ajv = addFormats(new Ajv({}), [...])
.addKeyword('kind')
.addKeyword('modifier')
.addSchema(Shared) // <-- Register Shared Types
//--------------------------------------------------------------------------------------------
//
// Create a TypeBox type
//
//--------------------------------------------------------------------------------------------
const User = Type.Object({
userId: Type.Ref(Shared, 'UserId'),
email: Type.Ref(Shared, 'Email'),
online: Type.Boolean()
}, { additionalProperties: false })
//--------------------------------------------------------------------------------------------
//
// Validate Data
//
//--------------------------------------------------------------------------------------------
const ok = ajv.validate(User, {
userId: '68b4b1d8-0db6-468d-b551-02069a692044',
email: '[email protected]',
online: true
}) // -> ok
Please refer to the official AJV documentation for more information.
TypeBox can be used to construct schemas for OpenAPI. However when using TypeBox for OpenAPI, users should be mindful of the semantic differences between JSON Schema and OpenAPI schematics.
For example, consider the following string type T
specified with an additional nullable
option. Note that while TypeBox allows one to pass unknown JSON schema options to a schema (such as nullable
), TypeBox does not understand that nullable
should result in a string | null
union when statically inferred.
const T = Type.String({ nullable: true }) // const T = {
// type: 'string'
// nullable: true
// }
type T = Static<typeof T> // type T = string // incorrect
To ensure TypeBox infers the correct static type in these scenarios, you can define a facade type by composing TypeBox's existing TSchema
types. The following creates a specialized OpenAPI Nullable<T>
type which uses the nullable
keyword as above. We return a TUnion<[T, TNull]>
as a facade as this is the closest approximation to the expected static type.
import { Type, Static, TSchema, TUnion, TNull } from '@sinclair/typebox'
function Nullable<T extends TSchema>(schema: T): TUnion<[T, TNull]> {
return { ...schema, nullable: true } as any // facade
}
const T = Nullable(Type.String()) // const T = {
// type: 'string'
// nullable: true
// }
type T = Static<typeof T> // type T = string | null