@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 type builder library that creates in-memory JSON Schema objects that can be statically resolved to TypeScript types. The schemas produced by this library are built to match the static type checking rules of the TypeScript compiler. TypeBox allows one to create a single unified type that can be both 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 4.0.3 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.Union([ │ type T = string | number │ const T = { │
│ Type.String(), │ │ anyOf: [{ │
│ Type.Number() │ │ type: 'string' │
│ ]) │ │ }, { │
│ │ │ type: 'number' │
│ │ │ }] │
│ │ │ } │
│ │ │ │
├────────────────────────────────┼─────────────────────────────┼────────────────────────────────┤
│ 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.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 properties 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 })
Reference Types can be used to reduce schema duplication. TypeBox provides supports referencing with the Type.Ref(...) and Type.Box(...) functions. The Type.Ref(...) function references into an existing type and Type.Box(...) provides a container for multiple referenceable types. To reference a type you must specify an $id on the target type being referenced. The following example shows referencing an existing string type.
const T = Type.String({ $id: 'T' }) // const T = {
// $id: 'T',
// type: 'string'
// }
const R = Type.Ref(T) // const R = {
// $ref: 'T'
// }
The Type.Box(...) function provides a way to group related types under a common namespace. The following example groups a set of related Vector types under the namespace Math3D which are later referenced in the Vertex structure below.
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']
// }
TypeBox provides support for creating recursive schemas. This is handled with the Type.Rec(...) function. The following will create a Node type that contains an array of inner Nodes. Note that due to current restrictions on TypeScript recursive inference, it's currently not possible for TypeBox to statically infer for recursive types. Instead TypeBox will resolve inner recursive types as any.
const Node = Type.Rec('Node', Self => // const Node = {
Type.Object({ // $id: 'Node',
id: Type.String(), // $ref: 'Node#/definitions/self',
nodes: Type.Array(Self), // 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 out of the box and expects users to select an appropriate JSON schema validation library for their needs. TypeBox schemas should match JSON Schema draft 2019-09 so any library capable of draft 2019-09 should be fine. A good library to use for validation 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({
id: Type.String({ format: 'uuid' }),
email: Type.String({ format: 'email' }),
online: Type.Boolean(),
}, { additionalProperties: false })
//--------------------------------------------------------------------------------------------
//
// Validate Data
//
//--------------------------------------------------------------------------------------------
const ok = ajv.validate(User, {
id: '68b4b1d8-0db6-468d-b551-02069a692044',
email: 'dave@domain.com',
online: true
}) // -> ok
Reference Types can be added to AJV with the ajv.addSchema(...) function. The following moves the id and email types above into a common box and registers it with the validator.
//--------------------------------------------------------------------------------------------
//
// Common Types
//
//--------------------------------------------------------------------------------------------
const Common = Type.Box('http://domain.com/common', {
UserId: Type.String({ format: 'uuid' }),
Email: Type.String({ format: 'email' })
})
//--------------------------------------------------------------------------------------------
//
// Setup AJV validator with the following options and formats
//
//--------------------------------------------------------------------------------------------
const ajv = addFormats(new Ajv({}), [...])
.addKeyword('kind')
.addKeyword('modifier')
.addSchema(Common) // <-- Register Common Types
//--------------------------------------------------------------------------------------------
//
// Create a TypeBox type
//
//--------------------------------------------------------------------------------------------
const User = Type.Object({
id: Type.Ref(Common, 'UserId'),
email: Type.Ref(Common, 'Email'),
online: Type.Boolean()
}, { additionalProperties: false })
//--------------------------------------------------------------------------------------------
//
// Validate Data
//
//--------------------------------------------------------------------------------------------
const ok = ajv.validate(User, {
id: '68b4b1d8-0db6-468d-b551-02069a692044',
email: 'dave@domain.com',
online: true
}) // -> ok
For more information on AJV, refer to the website located here.
FAQs
Json Schema Type Builder with Static Type Resolution for TypeScript
The npm package @sinclair/typebox receives a total of 11,903,364 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 1 open source maintainer collaborating on the project.
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