@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
import { Static, Type } from '@sinclair/typebox'
const T = Type.String() /* const T = { "type": "string" } */
type T = Static<typeof T> /* type T = string */
$ npm install @sinclair/typebox --save
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 { Type, Static } from '@sinclair/typebox'
//--------------------------------------------------------------------------------------------
//
// Let's say you have the following type ...
//
//--------------------------------------------------------------------------------------------
type Record = {
id: string,
name: string,
timestamp: number
}
//--------------------------------------------------------------------------------------------
//
// ... you can express this type in the following way.
//
//--------------------------------------------------------------------------------------------
const Record = Type.Object({ // const Record = {
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 Record = Static<typeof Record> // type Record = {
// id: string,
// name: string,
// timestamp: number
// }
//--------------------------------------------------------------------------------------------
//
// ... then use the type both as JSON schema and as a TypeScript type.
//
//--------------------------------------------------------------------------------------------
function receive(record: Record) { // ... as a type
if(JSON.validate(Record, { // ... as a schema
id: '42',
name: 'dave',
timestamp: Date.now()
})) {
// 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('foo') │ type T = 'foo' │ const T = { │
│ │ │ type: 'string', │
│ │ │ enum: ['foo'] │
│ │ │ } │
├────────────────────────────────┼─────────────────────────────┼─────────────────────────────┤
│ const T = Type.Array( │ type T = number[] │ const T = { │
│ Type.Number() │ │ type: 'array', │
│ ) │ │ items: { │
│ │ │ type: 'number' │
│ │ │ } │
│ │ │ } │
├────────────────────────────────┼─────────────────────────────┼─────────────────────────────┤
│ const T = Type.Dict( │ type T = { │ const T = { │
│ Type.Number() │ [key: string] │ type: 'object' │
│ ) │ } : number │ additionalProperties: { │
│ │ │ type: 'number' │
│ │ │ } │
│ │ │ } │
├────────────────────────────────┼─────────────────────────────┼─────────────────────────────┤
│ const T = Type.Object({ │ type T = { │ const T = { │
│ name: Type.String(), │ name: string, │ type: 'object', │
│ email: Type.String(), │ email: string │ properties: { │
│ }) │ } │ name: { │
│ │ │ type: 'string' │
│ │ │ }, │
│ │ │ email: { │
│ │ │ type: 'string' │
│ │ │ } │
│ │ │ }, │
│ │ │ required: [ │
│ │ │ 'name', │
│ │ │ 'email' │
│ │ │ ] |
│ │ │ } │
├────────────────────────────────┼─────────────────────────────┼─────────────────────────────┤
│ const T = Type.Tuple([ │ type T = [string, number] │ const T = { │
│ Type.String(), │ │ type: 'array', │
│ Type.Number() │ │ items: [ │
│ ]) │ │ { │
│ │ │ type: 'string' │
│ │ │ }, { │
│ │ │ type: 'number' │
│ │ │ } │
│ │ │ ], │
│ │ │ additionalItems: false, │
│ │ │ minItems: 2, │
│ │ │ maxItems: 2, │
│ │ │ } |
├────────────────────────────────┼─────────────────────────────┼─────────────────────────────┤
│ enum Foo { │ enum Foo { │ const T = { │
│ A, │ A, │ enum: [0, 1] │
│ B │ B │ } │
│ } │ } │ │
│ │ │ │
│ type T = Type.Enum(Foo) │ type T = Foo │ │
│ │ │ │
├────────────────────────────────┼─────────────────────────────┼─────────────────────────────┤
│ 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({ │ a: string │ allOf: [{ │
│ a: Type.String() │ } & { │ type: 'object', │
│ }), │ b: number │ properties: { │
│ Type.Object({ │ } │ a: { │
│ b: Type.Number() │ │ type: 'string' │
│ }) │ │ } │
│ }) │ │ }, │
│ │ │ required: ['a'] │
│ │ │ }, { │
│ │ │ type: 'object', │
│ │ │ properties: { │
│ │ │ b: { │
│ │ │ type: 'number' │
│ │ │ } │
│ │ │ }, │
│ │ │ required:['b'] │
│ │ │ }] │
│ │ │ } │
└────────────────────────────────┴─────────────────────────────┴─────────────────────────────┘
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 })
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'
// }
// }
// }
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' │
| │ │ } │
└────────────────────────────────┴─────────────────────────────┴─────────────────────────────┘
It is possible to create interfaces from TypeBox types. Consider the following code that creates a ControllerInterface type that has a single function createRecord(...). The following is how one would approach this in TypeScript.
interface CreateRecordRequest {
data: string
}
interface CreateRecordResponse {
id: string
}
interface ControllerInterface {
createRecord(record: CreateRecordRequest): Promise<CreateRecordResponse>
}
class Controller implements ControllerInterface {
async createRecord(record: CreateRecordRequest): Promise<CreateRecordResponse> {
return { id: '1' }
}
}
The following is the TypeBox equivalent.
import { Type, Static } from '@sinclair/typebox'
type CreateRecordRequest = Static<typeof CreateRecordRequest>
const CreateRecordRequest = Type.Object({
data: Type.String()
})
type CreateRecordResponse = Static<typeof CreateRecordResponse>
const CreateRecordResponse = Type.Object({
id: Type.String()
})
type ControllerInterface = Static<typeof ControllerInterface>
const ControllerInterface = Type.Object({
createRecord: Type.Function([CreateRecordRequest], Type.Promise(CreateRecordResponse))
})
class Controller implements ControllerInterface {
async createRecord(record: CreateRecordRequest): Promise<CreateRecordResponse> {
return { id: '1' }
}
}
Because TypeBox encodes the type information as JSON schema, it now becomes possible to reflect on the JSON schema to produce sharable metadata that can be used as machine readable documentation.
console.log(JSON.stringify(ControllerInterface, null, 2))
// outputs:
//
// {
// "type": "object",
// "properties": {
// "createRecord": {
// "type": "function",
// "arguments": [
// {
// "type": "object",
// "properties": {
// "data": {
// "type": "string"
// }
// },
// "required": [
// "data"
// ]
// }
// ],
// "returns": {
// "type": "promise",
// "item": {
// "type": "object",
// "properties": {
// "id": {
// "type": "string"
// }
// },
// "required": [
// "id"
// ]
// }
// }
// }
// },
// "required": [
// "createRecord"
// ]
// }
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 6 so any library capable of draft 6 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 { Type } from '@sinclair/typebox'
import addFormats from 'ajv-formats'
import Ajv from 'ajv'
// Setup
function setupAjv(): Ajv {
const ajv = new Ajv()
ajv.addKeyword('kind')
ajv.addKeyword('modifier')
return addFormats(ajv, [
'date-time',
'time',
'date',
'email',
'hostname',
'ipv4',
'ipv6',
'uri',
'uri-reference',
'uuid',
'uri-template',
'json-pointer',
'relative-json-pointer',
'regex'
])
}
// TypeBox
const User = Type.Object({
name: Type.String(),
email: Type.String({ format: 'email' })
})
// Validate
const isValid = setupAjv().validate(User, {
name: 'dave',
email: 'dave@domain.com'
})
//
// isValid -> true
//
FAQs
Json Schema Type Builder with Static Type Resolution for TypeScript
The npm package @sinclair/typebox receives a total of 28,689,911 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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