@sinclair/typebox
Advanced tools
The @sinclair/typebox package is a TypeScript utility designed to create type-safe schemas with a consistent syntax. It is primarily used for defining data structures with TypeScript types and validating data at runtime using a separate validation library like Ajv.
Type Creation
Allows the creation of TypeScript types for various data structures such as strings, numbers, objects, arrays, etc. The created types can be used for compile-time type checking and runtime validation.
{"const T = Type.String()"}Type Composition
Enables the composition of complex types by combining simpler types. This is useful for defining the shape of objects, with optional and required fields.
{"const UserType = Type.Object({ name: Type.String(), age: Type.Optional(Type.Number()) })"}Type Validation
Provides a way to validate data at runtime against the defined types using a validation library like Ajv. This ensures that the data conforms to the specified schema.
{"const T = Type.String(); const validate = ajv.compile(T); const isValid = validate('hello');"}Joi is a powerful schema description language and data validator for JavaScript. It allows for detailed descriptions of data structures with a wide range of validation options. Compared to @sinclair/typebox, Joi has a more extensive API and built-in validation without the need for an external library.
Yup is a JavaScript schema builder for value parsing and validation. It defines a schema with an expressive API and handles both validation and error messages. Unlike @sinclair/typebox, Yup includes its own validation methods and does not rely on TypeScript for type definitions.
Zod is a TypeScript-first schema declaration and validation library. It offers a similar experience to @sinclair/typebox by leveraging TypeScript for type safety while also providing runtime validation. Zod's API is designed to be more concise and it includes its own validation logic.
JSON Schema Type Builder with Static Type Resolution for TypeScript
$ 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 creates in-memory JSON Schema objects that can be statically inferred as 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 both statically asserted 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
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({ │ } │ x: { │
│ y: Type.Number() │ │ type: 'number' │
│ }) │ │ } │
│ }) │ │ }, │
│ │ │ required: ['x'] │
│ │ │ }, { │
│ │ │ type: 'object', │
│ │ │ properties: { │
│ │ │ y: { │
│ │ │ type: 'number' │
│ │ │ } │
│ │ │ }, │
│ │ │ required: ['y'] │
│ │ │ }] │
│ │ │ } │
│ │ │ │
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
│ 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 sometimes be helpful to organize shared referenced types under a common namespace. The Type.Namespace(...) 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.Namespace({ // const Math3D = {
Vector4: Type.Object({ // $id: 'Math3D',
x: Type.Number(), // $defs: {
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: { $ref: 'Math3D#/$defs/Vector4' },
}) // normal: { $ref: 'Math3D#/$defs/Vector3' },
// uv: { $ref: 'Math3D#/$defs/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), // $ref: 'Node#/$defs/self',
}), { $id: 'Node' }) // $defs: {
// self: {
// type: 'object',
// properties: {
// id: {
// type: 'string'
// },
// nodes: {
// type: 'array',
// items: {
// $ref: 'Node#/$defs/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 schemas contain the properties kind and modifier. These properties are provided to enable runtime type reflection on schemas, as well as helping TypeBox apply the appropriate static type inference rules. 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 necessary.
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 so users will need to select an appropriate JSON Schema validator for their needs. TypeBox schemas target 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: 'dave@domain.com',
online: true
}) // -> ok
Please refer to the official AJV documentation for additional information on using AJV.
TypeBox can be used to create schemas for OpenAPI, however users should be mindful of some disparities between the JSON Schema and OpenAPI for versions prior to OpenAPI 3.1. Two common instances where OpenAPI diverges is the handling nullable and string enum schemas types. The following shows how you can use TypeBox to construct these types.
import { Type, Static, TNull, TLiteral, TUnion, TSchema } from '@sinclair/typebox'
//--------------------------------------------------------------------------------------------
//
// Nullable<T>
//
//--------------------------------------------------------------------------------------------
function Nullable<T extends TSchema>(schema: T): TUnion<[T, TNull]> {
return { ...schema, nullable: true } as any
}
const T = Nullable(Type.String()) // const T = {
// type: 'string',
// nullable: true
// }
type T = Static<typeof T> // type T = string | null
//--------------------------------------------------------------------------------------------
//
// StringUnion<[...]>
//
//--------------------------------------------------------------------------------------------
type IntoStringUnion<T> = {[K in keyof T]: T[K] extends string ? TLiteral<T[K]>: never }
function StringUnion<T extends string[]>(values: [...T]): TUnion<IntoStringUnion<T>> {
return { enum: values } as any
}
const T = StringUnion(['A', 'B', 'C']) // const T = {
// enum: ['A', 'B', 'C']
// }
type T = Static<typeof T> // type T = 'A' | 'B' | 'C'
FAQs
Json Schema Type Builder with Static Type Resolution for TypeScript
The npm package @sinclair/typebox receives a total of 20,912,614 weekly downloads. As such, @sinclair/typebox popularity was classified as popular.
We found that @sinclair/typebox demonstrated a healthy version release cadence and project activity because the last version was released less than a year ago. It has 0 open source maintainers collaborating on the project.
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